diff --git a/.travis.yml b/.travis.yml
index 09c5056..d413499 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,9 +5,9 @@ addons:
 env:
   - RAILS_ENV=test
 script:
-  - sonar-scanner
   - bundle exec rails db:migrate
   - bundle exec rails spec
+  - sonar-scanner
 notifications:
   slack:
     secure: 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
diff --git a/app/controllers/matches_controller.rb b/app/controllers/matches_controller.rb
index c65b521..d64c60d 100644
--- a/app/controllers/matches_controller.rb
+++ b/app/controllers/matches_controller.rb
@@ -13,12 +13,14 @@ class MatchesController < ApplicationController
   # PATCH/PUT /matches/1
   def update
     new_state = match_params['state']
-    if new_state == 'finished'
-      # implement logic to move the winning team into the next stage
-      match_params['state'] = 'team1_won' # or 'team2_won' or 'undecided'
-      render json: {}, status: :not_implemented
-    end
     if @match.update(match_params)
+      if new_state == 'finished'
+        result = PopulateMatchBelowAndSave.call(match: @match) unless @match.group_match?
+        unless result.success?
+          render json: { error: 'Moving Team one stage down failed' }, status: :unprocessable_entity
+          return
+        end
+      end
       render json: @match
     else
       render json: @match.errors, status: :unprocessable_entity
diff --git a/app/controllers/tournaments_controller.rb b/app/controllers/tournaments_controller.rb
index 6a4a3e5..6f80705 100644
--- a/app/controllers/tournaments_controller.rb
+++ b/app/controllers/tournaments_controller.rb
@@ -38,14 +38,14 @@ class TournamentsController < ApplicationController
     if group_stage
       groups = organize_teams_in_groups(teams)
       # add groups to tournament
-      result = AddGroupStageToTournamentAndSaveTournamentToDatabase.call(tournament: tournament, groups: groups)
+      result = AddGroupStageToTournamentAndSave.call(tournament: tournament, groups: groups)
     else
       # convert teams parameter into Team objects
       teams = teams.map(&method(:find_or_create_team))
       # associate provided teams with tournament
       tournament.teams = teams
       # add playoff stage to tournament
-      result = AddPlayoffsToTournamentAndSaveTournamentToDatabase.call(tournament: tournament)
+      result = AddPlayoffsToTournamentAndSave.call(tournament: tournament)
     end
     # validate tournament
     unless tournament.valid?
diff --git a/app/interactors/add_group_stage_to_tournament.rb b/app/interactors/add_group_stage_to_tournament.rb
index 14b798c..d1d28e2 100644
--- a/app/interactors/add_group_stage_to_tournament.rb
+++ b/app/interactors/add_group_stage_to_tournament.rb
@@ -10,7 +10,7 @@ class AddGroupStageToTournament
     begin
       group_stage = GroupStageService.generate_group_stage(groups)
       tournament.stages = [group_stage]
-      context.tournament = tournament
+      context.object_to_save = tournament
     rescue StandardError
       context.fail!
     end
diff --git a/app/interactors/add_playoffs_to_tournament.rb b/app/interactors/add_playoffs_to_tournament.rb
index fbe7f25..9efc2ec 100644
--- a/app/interactors/add_playoffs_to_tournament.rb
+++ b/app/interactors/add_playoffs_to_tournament.rb
@@ -12,7 +12,7 @@ class AddPlayoffsToTournament
       else
         tournament.stages.concat playoff_stages
       end
-      context.tournament = tournament
+      context.object_to_save = tournament
     else
       context.fail!
     end
diff --git a/app/interactors/populate_match_below.rb b/app/interactors/populate_match_below.rb
new file mode 100644
index 0000000..96a58c3
--- /dev/null
+++ b/app/interactors/populate_match_below.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+class PopulateMatchBelow
+  include Interactor
+
+  def call
+    match = context.match
+    begin
+      objects_to_save = PlayoffStageService.populate_match_below(match)
+      context.object_to_save = objects_to_save
+    rescue StandardError
+      context.fail!
+    end
+  end
+end
diff --git a/app/interactors/save_application_record_object.rb b/app/interactors/save_application_record_object.rb
new file mode 100644
index 0000000..9239a78
--- /dev/null
+++ b/app/interactors/save_application_record_object.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class SaveApplicationRecordObject
+  include Interactor
+
+  def call
+    Array(context.object_to_save).flatten.each do |object|
+      context.fail! unless object.save
+    end
+  end
+end
diff --git a/app/interactors/save_tournament_to_database.rb b/app/interactors/save_tournament_to_database.rb
deleted file mode 100644
index 40acf12..0000000
--- a/app/interactors/save_tournament_to_database.rb
+++ /dev/null
@@ -1,13 +0,0 @@
-# frozen_string_literal: true
-
-class SaveTournamentToDatabase
-  include Interactor
-
-  def call
-    if context.tournament.save
-      nil
-    else
-      context.fail!
-    end
-  end
-end
diff --git a/app/models/match.rb b/app/models/match.rb
index 8ab9756..2779fa7 100644
--- a/app/models/match.rb
+++ b/app/models/match.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 class Match < ApplicationRecord
-  enum state: %i[single_team not_ready not_started in_progress team1_won team2_won undecided]
+  enum state: %i[single_team not_ready not_started in_progress finished undecided]
 
   belongs_to :stage, optional: true
   belongs_to :group, optional: true
@@ -19,23 +19,20 @@ class Match < ApplicationRecord
     stage ? stage.owner : group.owner
   end
 
-  private
+  def winner
+    return nil unless finished?
+    return nil if match_scores.first.points == match_scores.second.points
 
-  def stage_xor_group
-    errors.add(:stage_xor_group, 'Stage and Group missing or both present') unless stage.present? ^ group.present?
-  end
-
-  def evaluate_status
-    if score_team1 < score_team2
-      :team2_won
-    elsif score_team2 < score_team1
-      :team1_won
-    else
-      group_match? ? :undecided : :in_progress
-    end
+    match_scores.max_by(&:points).team
   end
 
   def group_match?
     group.present?
   end
+
+  private
+
+  def stage_xor_group
+    errors.add(:stage_xor_group, 'Stage and Group missing or both present') unless stage.present? ^ group.present?
+  end
 end
diff --git a/app/organizers/add_group_stage_to_tournament_and_save.rb b/app/organizers/add_group_stage_to_tournament_and_save.rb
new file mode 100644
index 0000000..b1f1012
--- /dev/null
+++ b/app/organizers/add_group_stage_to_tournament_and_save.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class AddGroupStageToTournamentAndSave
+  include Interactor::Organizer
+
+  organize AddGroupStageToTournament, SaveApplicationRecordObject
+end
diff --git a/app/organizers/add_group_stage_to_tournament_and_save_tournament_to_database.rb b/app/organizers/add_group_stage_to_tournament_and_save_tournament_to_database.rb
deleted file mode 100644
index 83710b5..0000000
--- a/app/organizers/add_group_stage_to_tournament_and_save_tournament_to_database.rb
+++ /dev/null
@@ -1,7 +0,0 @@
-# frozen_string_literal: true
-
-class AddGroupStageToTournamentAndSaveTournamentToDatabase
-  include Interactor::Organizer
-
-  organize AddGroupStageToTournament, SaveTournamentToDatabase
-end
diff --git a/app/organizers/add_playoffs_to_tournament_and_save.rb b/app/organizers/add_playoffs_to_tournament_and_save.rb
new file mode 100644
index 0000000..766add6
--- /dev/null
+++ b/app/organizers/add_playoffs_to_tournament_and_save.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class AddPlayoffsToTournamentAndSave
+  include Interactor::Organizer
+
+  organize AddPlayoffsToTournament, SaveApplicationRecordObject
+end
diff --git a/app/organizers/add_playoffs_to_tournament_and_save_tournament_to_database.rb b/app/organizers/add_playoffs_to_tournament_and_save_tournament_to_database.rb
deleted file mode 100644
index d4466a0..0000000
--- a/app/organizers/add_playoffs_to_tournament_and_save_tournament_to_database.rb
+++ /dev/null
@@ -1,7 +0,0 @@
-# frozen_string_literal: true
-
-class AddPlayoffsToTournamentAndSaveTournamentToDatabase
-  include Interactor::Organizer
-
-  organize AddPlayoffsToTournament, SaveTournamentToDatabase
-end
diff --git a/app/organizers/populate_match_below_and_save.rb b/app/organizers/populate_match_below_and_save.rb
new file mode 100644
index 0000000..e947b90
--- /dev/null
+++ b/app/organizers/populate_match_below_and_save.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class PopulateMatchBelowAndSave
+  include Interactor::Organizer
+
+  organize PopulateMatchBelow, SaveApplicationRecordObject
+end
diff --git a/app/services/playoff_stage_service.rb b/app/services/playoff_stage_service.rb
index 340a9a2..38ccabc 100644
--- a/app/services/playoff_stage_service.rb
+++ b/app/services/playoff_stage_service.rb
@@ -1,73 +1,149 @@
 # frozen_string_literal: true
 
 class PlayoffStageService
-  # Generates the playoff stage given the tournament
-  #
-  # @param teams [Array] The teams to generate the playoff stages with
-  # @return [Array] the generated playoff stages
-  def self.generate_playoff_stages(teams)
-    playoffs = []
-    stage_count = calculate_required_stage_count(teams.size)
-    # initial_matches are the matches in the first stage; this is the only stage filled with teams from the start on
-    initial_matches = MatchService.generate_matches(teams)
-    initial_stage = Stage.new level: stage_count - 1, matches: initial_matches
-    playoffs << initial_stage
-    # empty stages are the stages, the tournament is filled with to have the matches ready for later
-    empty_stages = generate_stages_with_empty_matches(stage_count - 1)
-    empty_stages.each do |stage|
-      playoffs << stage
+  class << self
+    # Generates the playoff stage given the tournament
+    #
+    # @param teams [Array] The teams to generate the playoff stages with
+    # @return [Array] the generated playoff stages
+    def generate_playoff_stages(teams)
+      playoffs = []
+      stage_count = calculate_required_stage_count(teams.size)
+      # initial_matches are the matches in the first stage; this is the only stage filled with teams from the start on
+      initial_matches = MatchService.generate_matches(teams)
+      initial_stage = Stage.new level: stage_count - 1, matches: initial_matches
+      playoffs << initial_stage
+      # empty stages are the stages, the tournament is filled with to have the matches ready for later
+      empty_stages = generate_stages_with_empty_matches(stage_count - 1)
+      empty_stages.each do |stage|
+        playoffs << stage
+      end
+      playoffs
     end
-    playoffs
-  end
 
-  # Generates the playoff stage given the tournament
-  #
-  # @param tournament [Tournament] The tournament to generate the playoff stages from
-  # @return [Array] the generated playoff stages
-  def self.generate_playoff_stages_from_tournament(tournament)
-    generate_playoff_stages tournament.teams
-  end
-
-  # Generates given number of empty stages
-  #
-  # @param stage_count [Integer] number of stages to generate
-  # @return [Array] the generated stages
-  def self.generate_stages_with_empty_matches(stage_count)
-    empty_stages = []
-    stage_count.times do |i|
-      stage = Stage.new level: i, matches: generate_empty_matches(2**i)
-      empty_stages << stage
+    # Generates the playoff stage given the tournament
+    #
+    # @param tournament [Tournament] The tournament to generate the playoff stages from
+    # @return [Array] the generated playoff stages
+    def generate_playoff_stages_from_tournament(tournament)
+      generate_playoff_stages tournament.teams
     end
-    # as we are generating the stages in the wrong order (starting with the lowest number of matches (which is
-    # the final stage)) they need to be reversed
-    empty_stages.reverse!
-  end
 
-  # Generates a number of empty matches to fill later stages
-  #
-  # @param amount [Integer] the amount of matches to generate
-  # @return [Array] the generated matches
-  def self.generate_empty_matches(amount)
-    matches = []
-    amount.times do |i|
-      match = Match.new state: :not_ready, position: i
-      matches << match
+    # Generates given number of empty stages
+    #
+    # @param stage_count [Integer] number of stages to generate
+    # @return [Array] the generated stages
+    def generate_stages_with_empty_matches(stage_count)
+      empty_stages = []
+      stage_count.times do |i|
+        stage = Stage.new level: i, matches: generate_empty_matches(2**i)
+        empty_stages << stage
+      end
+      # as we are generating the stages in the wrong order (starting with the lowest number of matches (which is
+      # the final stage)) they need to be reversed
+      empty_stages.reverse!
     end
-    matches
-  end
 
-  # Calculates how many stages are required for given number of teams
-  #
-  # @param number_of_teams [Integer] the teams number of teams to calculate amount of stages
-  # @return [Integer] amount of required stages
-  def self.calculate_required_stage_count(number_of_teams)
-    if number_of_teams == 1
-      1
-    else
-      # black voodoo magic
-      stage_count = Math.log(Utils.next_power_of_two(number_of_teams)) / Math.log(2)
-      stage_count -= 1 if Utils.po2?(number_of_teams)
-      stage_count.to_int
+    # Generates a number of empty matches to fill later stages
+    #
+    # @param amount [Integer] the amount of matches to generate
+    # @return [Array] the generated matches
+    def generate_empty_matches(amount)
+      matches = []
+      amount.times do |i|
+        match = Match.new state: :not_ready, position: i
+        matches << match
+      end
+      matches
+    end
+
+    # Calculates how many stages are required for given number of teams
+    #
+    # @param number_of_teams [Integer] the teams number of teams to calculate amount of stages
+    # @return [Integer] amount of required stages
+    def calculate_required_stage_count(number_of_teams)
+      if number_of_teams == 1
+        1
+      else
+        # black voodoo magic
+        stage_count = Math.log(Utils.next_power_of_two(number_of_teams)) / Math.log(2)
+        stage_count -= 1 if Utils.po2?(number_of_teams)
+        stage_count.to_int
+      end
+    end
+
+    # Populates the match below given match with the winners of the matches above
+    #
+    # @param current_match [Match] The Match which finished, the match below it gets populated
+    # @return [Array] the objects that changed and need to be saved
+    def populate_match_below(current_match)
+      current_stage = current_match.stage
+      next_stage = current_stage.tournament.stages.find { |s| s.level == current_stage.level - 1 }
+      # return if next stage does not exist (there are no matches after the finale)
+      return if next_stage.nil?
+
+      current_position = current_match.position
+
+      # a "companion" match is the one that with the selected match makes up the two matches
+      # of which the winners advance into the match below
+      # depending on the position of the match, the companion match is either on the left or right of it
+      companion_match = find_companion_match(current_position, current_stage)
+
+      match_below = next_stage.matches.find { |m| m.position == current_position / 2 }
+      match_scores = match_below.match_scores.sort_by(&:id)
+
+      winners = get_winners_of(companion_match, current_match)
+
+      # depending on the amount of match_scores already present we need to do different things
+      match_scores = assign_correct_match_scores!(match_scores, winners)
+
+      # If a match is not decided yet, it will return nil as winner.
+      # This is not allowed in Database. The following code filters out MatchScores that contain nil as team.
+      match_scores = match_scores.select { |ms| ms.team.present? }
+      match_below.match_scores = match_scores
+      match_below.state = if match_below.match_scores.empty? || match_below.match_scores.size == 1
+                            :not_ready
+                          elsif match_below.match_scores.size == 2
+                            :not_started
+                          else
+                            raise 'Unprocessable amount of match_scores found'
+                          end
+      [match_below, match_scores].flatten
+    end
+
+    private
+
+    def find_companion_match(current_position, current_stage)
+      companion_match_position = current_position.even? ? current_position + 1 : current_position - 1
+      current_stage.matches.find { |m| m.position == companion_match_position }
+    end
+
+    def assign_correct_match_scores!(match_scores, winners)
+      case match_scores.size
+      when 0
+        # when 0 match_scores are already there we create both of them with the respective winner from above
+        match_scores = winners.map { |winner| MatchScore.new(team: winner) }
+      when 1
+        # when 1 match_score is present, we need to check which team is contained within and add the other team as well
+        if match_scores.first.team == winners.first
+          match_scores.push MatchScore.new(team: winners.second)
+        elsif match_scores.first.team == winners.second
+          match_scores.push MatchScore.new(team: winners.first)
+        else
+          match_scores.first.destroy
+          match_scores = winners.map { |winner| MatchScore.new(team: winner) }
+        end
+      when 2
+        # when 2 match_scores are present, the teams just get overwritten
+        match_scores.first.team = winners.first
+        match_scores.second.team = winners.second
+      end
+      match_scores
+    end
+
+    def get_winners_of(companion_match, current_match)
+      matches = [current_match, companion_match].sort_by(&:position)
+      matches.map(&:winner)
     end
   end
 end
diff --git a/spec/controllers/matches_controller_spec.rb b/spec/controllers/matches_controller_spec.rb
index 10b0a30..7606be1 100644
--- a/spec/controllers/matches_controller_spec.rb
+++ b/spec/controllers/matches_controller_spec.rb
@@ -5,6 +5,9 @@ require 'rails_helper'
 RSpec.describe MatchesController, type: :controller do
   before do
     @match = create(:match, state: :not_started)
+    @amount_of_stages = 2
+    @tournament = create(:stage_tournament, stage_count: @amount_of_stages)
+    @running_playoff_match = @tournament.stages.find_by(level: @amount_of_stages).matches.first
     @match.match_scores = create_pair(:match_score)
   end
 
@@ -32,7 +35,7 @@ RSpec.describe MatchesController, type: :controller do
 
     let(:invalid_update) do
       {
-        state: 'team1_won'
+        state: 'finished'
       }
     end
 
@@ -55,6 +58,48 @@ RSpec.describe MatchesController, type: :controller do
           body = deserialize_response response
           expect(body[:state]).to eq(valid_update[:state])
         end
+
+        context 'on a running playoff match' do
+          let(:finished) do
+            {
+              state: 'finished'
+            }
+          end
+
+          before(:each) do
+            apply_authentication_headers_for @running_playoff_match.owner
+          end
+
+          before do
+            @running_playoff_match.match_scores.each_with_index do |ms, i|
+              ms.points = i
+              ms.save!
+            end
+            put :update, params: { id: @running_playoff_match.to_param }.merge(finished)
+            @running_playoff_match.reload
+          end
+
+          it 'updates the matches status' do
+            expect(response).to be_successful
+            expect(@running_playoff_match.state).to eq(finished[:state])
+          end
+
+          describe 'updates the match below' do
+            before do
+              @match_below = @tournament.stages.find_by(level: @amount_of_stages - 1).matches
+                                        .find_by(position: @running_playoff_match.position / 2).reload
+            end
+
+            it 'with the right teams' do
+              expect(@running_playoff_match.winner).to be_a(Team)
+              expect(@match_below.teams).to include(@running_playoff_match.winner)
+            end
+
+            it 'with the right status' do
+              expect(@match_below.state).to eq('not_ready')
+            end
+          end
+        end
       end
 
       context 'with invalid params' do
diff --git a/spec/factories/matches.rb b/spec/factories/matches.rb
index 030c87c..43fb55d 100644
--- a/spec/factories/matches.rb
+++ b/spec/factories/matches.rb
@@ -27,7 +27,7 @@ FactoryBot.define do
         # random number generated by blapplications
         match.match_scores.first.points += 1
       end
-      state { :team1_won }
+      state { :finished }
     end
   end
 
@@ -51,7 +51,7 @@ FactoryBot.define do
       after(:create) do |match, evaluator|
         match.match_scores = create_list(:match_score, evaluator.match_scores_count, points: 3)
       end
-      state { :team1_won }
+      state { :finished }
     end
   end
 end
diff --git a/spec/factories/tournaments.rb b/spec/factories/tournaments.rb
index 6d7098e..637564c 100644
--- a/spec/factories/tournaments.rb
+++ b/spec/factories/tournaments.rb
@@ -32,8 +32,14 @@ FactoryBot.define do
             :playoff_stage,
             level: level,
             match_count: -1,
-            match_type: evaluator.stage_count ? :running_playoff_match : :empty_prepared_playoff_match
+            match_type: level == evaluator.stage_count ? :running_playoff_match : :empty_prepared_playoff_match
           )
+          tournament.stages.each do |stage|
+            stage.matches.each_with_index do |match, i|
+              match.position = i
+              match.save!
+            end
+          end
         end
       end
 
diff --git a/spec/interactors/add_group_stage_to_tournament_interactor_spec.rb b/spec/interactors/add_group_stage_to_tournament_interactor_spec.rb
index b64c752..d7a3208 100644
--- a/spec/interactors/add_group_stage_to_tournament_interactor_spec.rb
+++ b/spec/interactors/add_group_stage_to_tournament_interactor_spec.rb
@@ -10,8 +10,8 @@ RSpec.describe AddGroupStageToTournament do
   end
 
   before do
-    @empty_tournament = create(:stage_tournament, stage_count: 0)
-    @group_stage_tournament = create(:group_stage_tournament)
+    @empty_tournament = create(:stageless_tournament)
+    @group_stage_tournament = create(:group_stage_only_tournament, group_count: 0)
     @group_stage = create(:group_stage)
     @groups = Hash[1 => create_list(:team, 4), 2 => create_list(:team, 4)].values
   end
diff --git a/spec/interactors/add_playoffs_to_tournament_interactor_spec.rb b/spec/interactors/add_playoffs_to_tournament_interactor_spec.rb
index 056dc2b..884f0e8 100644
--- a/spec/interactors/add_playoffs_to_tournament_interactor_spec.rb
+++ b/spec/interactors/add_playoffs_to_tournament_interactor_spec.rb
@@ -14,10 +14,10 @@ RSpec.describe AddPlayoffsToTournament do
   end
 
   before do
-    @group_stage_tournament = create(:stage_tournament)
-    @playoff_stage_tournament = create(:tournament)
-    @full_tournament = create(:stage_tournament, stage_count: 5)
-    @stages = create_list(:stage, 5)
+    @group_stage_tournament = create(:group_stage_only_tournament, group_count: 0)
+    @playoff_stage_tournament = create(:stageless_tournament)
+    @full_tournament = create(:dummy_stage_tournament)
+    @stages = create_list(:stage, 3)
   end
 
   context 'PlayoffStageService mocked' do
diff --git a/spec/interactors/populate_match_below_interactor_spec.rb b/spec/interactors/populate_match_below_interactor_spec.rb
new file mode 100644
index 0000000..8b751e0
--- /dev/null
+++ b/spec/interactors/populate_match_below_interactor_spec.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+RSpec.describe PopulateMatchBelow do
+  before do
+    @match = create(:match)
+    @objects_to_save = [create(:match), create_list(:match_score, 2)]
+  end
+
+  context 'no exception' do
+    let(:context) do
+      PopulateMatchBelow.call(match: @match)
+    end
+    before do
+      allow(PlayoffStageService)
+        .to receive(:populate_match_below).with(@match)
+                                          .and_return(@objects_to_save)
+    end
+
+    it 'succeeds' do
+      expect(context).to be_a_success
+    end
+
+    it 'provides the objects to save' do
+      expect(context.object_to_save).to match_array(@objects_to_save)
+    end
+  end
+
+  context 'exception is thrown' do
+    let(:context) do
+      PopulateMatchBelow.call(match: @match)
+    end
+    before do
+      allow(PlayoffStageService)
+        .to receive(:populate_match_below).with(@match)
+                                          .and_throw('This failed :(')
+    end
+
+    it 'fails' do
+      test = context.failure?
+      expect(test).to eq(true)
+    end
+  end
+end
diff --git a/spec/interactors/save_tournament_to_database_interactor_spec.rb b/spec/interactors/save_application_record_object_to_database_interactor_spec.rb
similarity index 72%
rename from spec/interactors/save_tournament_to_database_interactor_spec.rb
rename to spec/interactors/save_application_record_object_to_database_interactor_spec.rb
index b10bba5..ce2edb3 100644
--- a/spec/interactors/save_tournament_to_database_interactor_spec.rb
+++ b/spec/interactors/save_application_record_object_to_database_interactor_spec.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-RSpec.describe SaveTournamentToDatabase do
+RSpec.describe SaveApplicationRecordObject do
   before do
     @tournament = create(:tournament)
   end
 
   context 'save succeeds' do
     let(:context) do
-      SaveTournamentToDatabase.call(tournament: @tournament)
+      SaveApplicationRecordObject.call(object_to_save: @tournament)
     end
     before do
       expect_any_instance_of(Tournament)
@@ -19,13 +19,13 @@ RSpec.describe SaveTournamentToDatabase do
     end
 
     it 'provides the tournament' do
-      expect(context.tournament).to eq(@tournament)
+      expect(context.object_to_save).to eq(@tournament)
     end
   end
 
   context 'save fails' do
     let(:context) do
-      SaveTournamentToDatabase.call(tournament: @tournament)
+      SaveApplicationRecordObject.call(object_to_save: @tournament)
     end
     before do
       expect_any_instance_of(Tournament)
diff --git a/spec/models/match_spec.rb b/spec/models/match_spec.rb
index 5acec23..0d4656c 100644
--- a/spec/models/match_spec.rb
+++ b/spec/models/match_spec.rb
@@ -43,6 +43,20 @@ RSpec.describe Match, type: :model do
     end
   end
 
+  context '#winner' do
+    it 'returns a winner Team for a decided match' do
+      decided_playoff_match = create(:decided_playoff_match)
+      winning_team_match_score = decided_playoff_match.match_scores.first
+      winning_team_match_score.points = 9999
+      winning_team = winning_team_match_score.team
+      expect(decided_playoff_match.winner).to be winning_team
+    end
+
+    it 'returns nil for an undecided match' do
+      expect(create(:undecided_group_match).winner).to be(nil)
+    end
+  end
+
   context '#teams' do
     before do
       @playoff_match = create(:running_playoff_match)
diff --git a/spec/services/playoff_stage_service_spec.rb b/spec/services/playoff_stage_service_spec.rb
index 46dfe55..91e3149 100644
--- a/spec/services/playoff_stage_service_spec.rb
+++ b/spec/services/playoff_stage_service_spec.rb
@@ -80,4 +80,108 @@ RSpec.describe PlayoffStageService do
       end
     end
   end
+
+  describe '#populate_match_below' do
+    before :each do
+      @tournament = create(:stage_tournament, stage_count: 2)
+      @match = @tournament.stages.find { |s| s.level == 2 }.matches.first
+      @match.state = :finished
+      @match.match_scores.each_with_index do |ms, i|
+        ms.points = i
+        ms.save
+      end
+      @match.save
+      @companion_match = @tournament.stages.find { |s| s.level == 2 }.matches.second
+      @companion_match.match_scores.each_with_index do |ms, i|
+        ms.points = i
+        ms.save
+      end
+      @match_to_find = @tournament.stages.find { |s| s.level == 1 }.matches.first
+    end
+
+    context 'match below has no match_scores' do
+      before do
+        @match_to_find.match_scores = []
+        @match_to_find.save
+        @test = PlayoffStageService.populate_match_below(@match).first
+      end
+
+      it 'finds the correct match and adds two new match_scores to it' do
+        expect(@match_to_find.teams).to match_array(@match.winner)
+      end
+
+      it 'finds the correct match and changes its state' do
+        expect(@match_to_find.state).to eq('not_ready')
+      end
+    end
+
+    context 'match below has one match_score with the winning team' do
+      before do
+        @match_to_find.match_scores = create_list(:match_score, 1, team: @match.winner)
+        @match_to_find.save
+        @test = PlayoffStageService.populate_match_below(@match).first
+      end
+
+      it 'finds the correct match and adds no match_score' do
+        expect(@test.teams).to match_array(@match.winner)
+      end
+
+      it 'finds the correct match and changes its state' do
+        expect(@test.state).to eq('not_ready')
+      end
+    end
+
+    context 'match below has one match_score with an unknown team' do
+      before do
+        @match_to_find.match_scores = create_list(:match_score, 1, team: create(:team), points: 1337)
+        @match_to_find.save
+        @test = PlayoffStageService.populate_match_below(@match).first
+      end
+
+      it 'finds the correct match and replaces the match_score' do
+        expect(@test.teams).to match_array(@match.winner)
+        expect(@test.match_scores.first.points).to_not be(1337)
+      end
+
+      it 'finds the correct match and changes its state' do
+        expect(@test.state).to eq('not_ready')
+      end
+    end
+
+    context 'match below has one match_score with the correct team' do
+      before do
+        @match_to_find.match_scores = create_list(:match_score, 1, team: @match.winner, points: 42)
+        @match_to_find.save
+        @test = PlayoffStageService.populate_match_below(@match).first
+      end
+
+      it 'finds the correct match and replaces nothing' do
+        expect(@test.teams).to match_array(@match.winner)
+        expect(@test.match_scores.first.points).to be(42)
+      end
+
+      it 'finds the correct match and changes its state' do
+        expect(@test.state).to eq('not_ready')
+      end
+    end
+
+    context 'match below has two match_scores with the correct teams' do
+      before do
+        @companion_match.state = :finished
+        @companion_match.save
+        @match_to_find.match_scores = [create(:match_score, team: @match.winner),
+                                       create(:match_score, team: @companion_match.winner)]
+        @match_to_find.save
+        @test = PlayoffStageService.populate_match_below(@match).first
+      end
+
+      it 'finds the correct match and replaces nothing' do
+        expect(@test.teams).to match_array([@match.winner, @companion_match.winner])
+      end
+
+      it 'finds the correct match and changes its state' do
+        expect(@test.state).to eq('not_started')
+      end
+    end
+  end
 end