diff --git a/app/controllers/match_scores_controller.rb b/app/controllers/match_scores_controller.rb
index 92f7dc0..f4d3014 100644
--- a/app/controllers/match_scores_controller.rb
+++ b/app/controllers/match_scores_controller.rb
@@ -29,6 +29,6 @@ class MatchScoresController < ApplicationController
 
   # Only allow a trusted parameter "white list" through.
   def match_score_params
-    params.slice(:points).permit!
+    params.slice(:points, :hidden_points).permit!
   end
 end
diff --git a/app/controllers/matches_controller.rb b/app/controllers/matches_controller.rb
index 5224479..353e102 100644
--- a/app/controllers/matches_controller.rb
+++ b/app/controllers/matches_controller.rb
@@ -2,8 +2,11 @@
 
 class MatchesController < ApplicationController
   before_action :set_match, only: %i[show update]
+  before_action :set_group, only: %i[create]
+  before_action :authenticate_user!, only: %i[create update]
   before_action :validate_params, only: %i[update]
   before_action -> { require_owner! @match.owner }, only: %i[update]
+  before_action -> { require_owner! @group.owner }, only: %i[create]
   before_action :set_tournament, only: %i[index]
 
   # GET/tournaments/1/matches
@@ -44,6 +47,20 @@ class MatchesController < ApplicationController
     render json: @match, include: %w[match_scores.points match_scores.team bets]
   end
 
+  # POST /groups/:group_id/matches
+  def create
+    match = build_decider_match
+
+    if match.errors.any?
+      render json: match.errors, status: :unprocessable_entity
+    elsif match.save
+      UpdateGroupsGroupScoresAndSave.call(group: @group)
+      render json: match, include: %w[match_scores.team group], status: :created
+    else
+      render json: match.errors, status: :unprocessable_entity
+    end
+  end
+
   # PATCH/PUT /matches/1
   def update
     new_state = match_params['state']
@@ -112,7 +129,32 @@ class MatchesController < ApplicationController
     @tournament = Tournament.find(params[:tournament_id])
   end
 
+  def set_group
+    @group = Group.find(params[:group_id])
+  end
+
   def match_params
     params.slice(:state).permit!
   end
+
+  def create_match_params
+    params.slice(:team_ids).permit(team_ids: [])
+  end
+
+  def build_decider_match
+    team_ids = create_match_params[:team_ids].to_a.map(&:to_i).uniq
+    teams = @group.teams.select { |team| team_ids.include?(team.id) }
+
+    Match.new(
+      group: @group,
+      state: :not_started,
+      position: (@group.matches.maximum(:position) || -1) + 1,
+      decider: true,
+      match_scores: teams.map { |team| MatchScore.new(team: team) }
+    ).tap do |match|
+      if team_ids.size != 2 || teams.size != 2
+        match.errors.add(:team_ids, 'must contain exactly two teams from this group')
+      end
+    end
+  end
 end
diff --git a/app/controllers/stages_controller.rb b/app/controllers/stages_controller.rb
index cdc5f1b..800204d 100644
--- a/app/controllers/stages_controller.rb
+++ b/app/controllers/stages_controller.rb
@@ -45,6 +45,22 @@ class StagesController < ApplicationController
       raise ActiveRecord::Rollback
     end
 
+    @stage.groups.each do |group|
+      next if UpdateGroupsGroupScoresAndSave.call(group: group).success?
+
+      render json: { error: 'Updating group scores failed' }, status: :unprocessable_entity
+      raise ActiveRecord::Rollback
+    end
+
+    blocking_ties = GroupStageService.blocking_ties_for(@stage)
+    if blocking_ties.any?
+      render json: {
+        error: 'Playoffs cannot be generated yet because a decider match is required for an advancing place',
+        blocking_ties: blocking_ties
+      }, status: :unprocessable_entity
+      raise ActiveRecord::Rollback
+    end
+
     return if AddPlayoffsToTournamentAndSave.call(tournament: @stage.tournament,
                                                   teams: GroupStageService.get_advancing_teams(@stage)).success?
 
diff --git a/app/models/group_score.rb b/app/models/group_score.rb
index 020ba81..325efa5 100644
--- a/app/models/group_score.rb
+++ b/app/models/group_score.rb
@@ -23,6 +23,8 @@ class GroupScore < ApplicationRecord
         public_send(COMPARISON_ATTRIBUTES[comparison_reason[:resolved_by]])
     when :direct_comparison
       comparison_reason[:direct_comparison_result] == :won ? -1 : 1
+    when :hidden_points
+      comparison_reason[:hidden_points_result] == :won ? -1 : 1
     else
       0
     end
@@ -36,16 +38,23 @@ class GroupScore < ApplicationRecord
       return {
         resolved_by: reason,
         tied: false,
-        direct_comparison_result: nil
+        direct_comparison_result: nil,
+        hidden_points_result: :not_played,
+        direct_comparison_match_id: nil,
+        decider_match_id: nil
       }
     end
 
     direct_comparison_result = direct_comparison_result_against(other)
+    hidden_points_result = hidden_points_result_against(other)
 
     {
-      resolved_by: direct_comparison_result.nil? ? :tie : :direct_comparison,
-      tied: direct_comparison_result.nil?,
-      direct_comparison_result: direct_comparison_result || direct_comparison_tie_reason_against(other)
+      resolved_by: resolved_by_for(direct_comparison_result, hidden_points_result),
+      tied: direct_comparison_result.nil? && hidden_points_result.nil?,
+      direct_comparison_result: direct_comparison_result || direct_comparison_tie_reason_against(other),
+      hidden_points_result: hidden_points_result || hidden_points_tie_reason_against(other),
+      direct_comparison_match_id: direct_comparison_match_against(other)&.id,
+      decider_match_id: decider_match_against(other)&.id
     }
   end
 
@@ -68,11 +77,47 @@ class GroupScore < ApplicationRecord
     :draw
   end
 
+  def hidden_points_result_against(other)
+    decider_match = decider_match_against(other)
+    return nil if decider_match.nil? || !decider_match.finished?
+
+    team_hidden_points = decider_match.hidden_points_of(team)
+    other_team_hidden_points = decider_match.hidden_points_of(other.team)
+    return :won if team_hidden_points > other_team_hidden_points
+    return :lost if team_hidden_points < other_team_hidden_points
+
+    nil
+  end
+
+  def hidden_points_tie_reason_against(other)
+    decider_match = decider_match_against(other)
+    return :not_played if decider_match.nil? || !decider_match.finished?
+
+    :draw
+  end
+
   private
 
+  def resolved_by_for(direct_comparison_result, hidden_points_result)
+    return :direct_comparison unless direct_comparison_result.nil?
+    return :hidden_points unless hidden_points_result.nil?
+
+    :tie
+  end
+
   def direct_comparison_match_against(other)
-    group.matches.reload.find do |match|
-      match.finished? && match.teams.include?(team) && match.teams.include?(other.team)
-    end
+    comparison_match_against(other, decider: false)
+  end
+
+  def decider_match_against(other)
+    comparison_match_against(other, decider: true)
+  end
+
+  def comparison_match_against(other, decider:)
+    group.matches.reload
+         .select do |match|
+           match.decider? == decider && match.teams.include?(team) && match.teams.include?(other.team)
+         end
+         .max_by(&:position)
   end
 end
diff --git a/app/models/match.rb b/app/models/match.rb
index 6f0a089..9500c65 100644
--- a/app/models/match.rb
+++ b/app/models/match.rb
@@ -23,9 +23,10 @@ class Match < ApplicationRecord
   end
 
   def current_leading_team
-    return nil if match_scores.first.points == match_scores.second.points
+    return nil if match_scores.size < 2
+    return nil if score_value_for(match_scores.first) == score_value_for(match_scores.second)
 
-    match_scores.max_by(&:points).team
+    match_scores.max_by { |match_score| score_value_for(match_score) }.team
   end
 
   def winner
@@ -39,14 +40,19 @@ class Match < ApplicationRecord
   end
 
   def scored_points_of(team)
+    return 0 if decider?
+
     teams.include?(team) ? match_scores.find_by(team: team).points : 0
   end
 
   def received_points_of(team)
+    return 0 if decider?
+
     teams.include?(team) ? match_scores.find { |ms| ms.team != team }.points : 0
   end
 
   def group_points_of(team)
+    return 0 if decider?
     return 0 unless (finished? || in_progress?) && teams.include?(team)
 
     case current_leading_team
@@ -59,9 +65,17 @@ class Match < ApplicationRecord
     end
   end
 
+  def hidden_points_of(team)
+    teams.include?(team) ? match_scores.find_by(team: team).hidden_points : 0
+  end
+
   private
 
   def stage_xor_group
     errors.add(:stage_xor_group, 'Stage and Group missing or both present') unless stage.present? ^ group.present?
   end
+
+  def score_value_for(match_score)
+    decider? ? match_score.hidden_points : match_score.points
+  end
 end
diff --git a/app/models/stage.rb b/app/models/stage.rb
index 97eb036..3466c8e 100644
--- a/app/models/stage.rb
+++ b/app/models/stage.rb
@@ -23,7 +23,8 @@ class Stage < ApplicationRecord
     return matches.find { |m| m.state != 'finished' }.nil? unless matches.size.zero?
 
     unless groups.size.zero? && groups.map(&:matches).flatten.size.zero?
-      return groups.map(&:matches).flatten.find { |m| m.state != 'finished' }.nil?
+      relevant_matches = groups.map(&:matches).flatten.reject(&:decider?)
+      return relevant_matches.find { |m| m.state != 'finished' }.nil?
     end
 
     false
diff --git a/app/serializers/match_score_serializer.rb b/app/serializers/match_score_serializer.rb
index bb62f7e..21991cc 100644
--- a/app/serializers/match_score_serializer.rb
+++ b/app/serializers/match_score_serializer.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 class MatchScoreSerializer < ApplicationSerializer
-  attributes :points
+  attributes :points, :hidden_points
 
   belongs_to :team
 end
diff --git a/app/serializers/match_serializer.rb b/app/serializers/match_serializer.rb
index 28b7d1a..50feade 100644
--- a/app/serializers/match_serializer.rb
+++ b/app/serializers/match_serializer.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 class MatchSerializer < ApplicationSerializer
-  attributes :state, :position, :winner
+  attributes :state, :position, :winner, :decider
 
   def winner
     ActiveModelSerializers::SerializableResource.new(object.winner).as_json
diff --git a/app/services/group_stage_service.rb b/app/services/group_stage_service.rb
index e9fc32d..735fd4d 100644
--- a/app/services/group_stage_service.rb
+++ b/app/services/group_stage_service.rb
@@ -112,12 +112,38 @@ class GroupStageService
         compared_with_team_id: compared_group_score.team.id,
         compared_with_team_name: compared_group_score.team.name,
         direct_comparison_result: comparison_reason[:direct_comparison_result].to_s,
+        direct_comparison_match_id: comparison_reason[:direct_comparison_match_id],
+        hidden_points_result: comparison_reason[:hidden_points_result].to_s,
+        decider_match_id: comparison_reason[:decider_match_id],
         tied: comparison_reason[:tied],
         needs_decider_match: comparison_reason[:tied] &&
           unresolved_tie_crosses_advancing_cutoff?(sorted_group_scores, group_score, advancing_slots_for_group(group_score.group))
       }
     end
 
+    def blocking_ties_for(group_stage)
+      return [] if group_stage.nil?
+
+      group_stage.groups.flat_map do |group|
+        sorted_scores = group.group_scores.reload.sort
+        sorted_scores.filter_map do |group_score|
+          decision = ranking_decision_for(group_score)
+          next unless decision&.fetch(:needs_decider_match, false)
+
+          comparison_team_id = decision[:compared_with_team_id]
+          next if comparison_team_id.nil? || group_score.team.id > comparison_team_id
+
+          {
+            group_id: group.id,
+            group_number: group.number,
+            team_ids: [group_score.team.id, comparison_team_id],
+            team_names: [group_score.team.name, decision[:compared_with_team_name]],
+            ranking_decision: decision
+          }
+        end
+      end
+    end
+
     # Returns all teams advancing to playoff stage from given group stage
     # They are ordered in such a way, that PlayoffStageService will correctly match the teams
     #
diff --git a/config/routes.rb b/config/routes.rb
index 9a6cf02..0351e81 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -9,6 +9,9 @@ Rails.application.routes.draw do
   resources :matches, only: %i[show update] do
     resources :bets, only: %i[index create]
   end
+  resources :groups, only: %i[show] do
+    resources :matches, only: %i[create]
+  end
   resources :stages, only: %i[show update]
   resources :teams, only: %i[show update]
   resources :tournaments do
@@ -20,7 +23,5 @@ Rails.application.routes.draw do
     end
   end
   resources :match_scores, only: %i[show update]
-  resources :groups, only: %i[show]
-
   get 'healthz', to: 'health#index'
 end
diff --git a/db/migrate/20260412110000_add_decider_support_to_group_matches.rb b/db/migrate/20260412110000_add_decider_support_to_group_matches.rb
new file mode 100644
index 0000000..ece1da6
--- /dev/null
+++ b/db/migrate/20260412110000_add_decider_support_to_group_matches.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class AddDeciderSupportToGroupMatches < ActiveRecord::Migration[7.0]
+  def change
+    add_column :matches, :decider, :boolean, null: false, default: false
+    add_column :match_scores, :hidden_points, :integer, null: false, default: 0
+  end
+end
diff --git a/spec/controllers/groups_controller_spec.rb b/spec/controllers/groups_controller_spec.rb
index 111b54a..5afecae 100644
--- a/spec/controllers/groups_controller_spec.rb
+++ b/spec/controllers/groups_controller_spec.rb
@@ -50,6 +50,7 @@ RSpec.describe GroupsController, type: :controller do
         resolved_by: 'direct_comparison',
         compared_with_team_name: 'B',
         direct_comparison_result: 'won',
+        hidden_points_result: 'not_played',
         tied: false,
         needs_decider_match: false
       )
@@ -57,6 +58,7 @@ RSpec.describe GroupsController, type: :controller do
         resolved_by: 'direct_comparison',
         compared_with_team_name: 'A',
         direct_comparison_result: 'lost',
+        hidden_points_result: 'not_played',
         tied: false,
         needs_decider_match: false
       )
diff --git a/spec/controllers/match_scores_controller_spec.rb b/spec/controllers/match_scores_controller_spec.rb
index 8e34133..a108f40 100644
--- a/spec/controllers/match_scores_controller_spec.rb
+++ b/spec/controllers/match_scores_controller_spec.rb
@@ -25,7 +25,8 @@ RSpec.describe MatchScoresController, type: :controller do
   describe 'PUT #update' do
     let(:valid_update) do
       {
-        points: 42
+        points: 42,
+        hidden_points: 13
       }
     end
 
@@ -39,6 +40,7 @@ RSpec.describe MatchScoresController, type: :controller do
             put :update, params: { id: @match_score.to_param }.merge(valid_update)
             @match_score.reload
             expect(@match_score.points).to eq(valid_update[:points])
+            expect(@match_score.hidden_points).to eq(valid_update[:hidden_points])
           end
 
           it 'renders a response with the updated team' do
@@ -46,6 +48,7 @@ RSpec.describe MatchScoresController, type: :controller do
             expect(response).to be_successful
             body = deserialize_response response
             expect(body[:points]).to eq(valid_update[:points])
+            expect(body[:hidden_points]).to eq(valid_update[:hidden_points])
           end
         end
 
@@ -86,7 +89,8 @@ RSpec.describe MatchScoresController, type: :controller do
 
     let(:valid_update) do
       {
-        points: 42
+        points: 42,
+        hidden_points: 13
       }
     end
 
diff --git a/spec/controllers/matches_controller_spec.rb b/spec/controllers/matches_controller_spec.rb
index a283b63..6e270dc 100644
--- a/spec/controllers/matches_controller_spec.rb
+++ b/spec/controllers/matches_controller_spec.rb
@@ -61,6 +61,41 @@ RSpec.describe MatchesController, type: :controller do
     end
   end
 
+  describe 'POST #create' do
+    let(:group_stage_tournament) { create(:group_stage_tournament, group_count: 1, match_factory: :finished_group_match) }
+    let(:group) { group_stage_tournament.stages.find_by(level: -1).groups.first }
+    let(:team_ids) { group.teams.first(2).map(&:id) }
+
+    context 'as owner' do
+      before do
+        apply_authentication_headers_for group.owner
+      end
+
+      it 'creates a decider match at the end of the group' do
+        expect do
+          post :create, params: { group_id: group.to_param, team_ids: team_ids }
+        end.to change { group.matches.reload.count }.by(1)
+
+        expect(response).to have_http_status(:created)
+        created_match = group.matches.reload.max_by(&:position)
+        expect(created_match.decider?).to eq(true)
+        expect(created_match.state).to eq('not_started')
+        expect(created_match.teams.map(&:id)).to match_array(team_ids)
+      end
+    end
+
+    context 'with invalid teams' do
+      before do
+        apply_authentication_headers_for group.owner
+      end
+
+      it 'rejects the request' do
+        post :create, params: { group_id: group.to_param, team_ids: [group.teams.first.id] }
+        expect(response).to have_http_status(:unprocessable_entity)
+      end
+    end
+  end
+
   describe 'POST #update' do
     context 'on a running playoff match' do
       let(:valid_update) do
diff --git a/spec/controllers/stages_controller_spec.rb b/spec/controllers/stages_controller_spec.rb
index a292400..8a66ced 100644
--- a/spec/controllers/stages_controller_spec.rb
+++ b/spec/controllers/stages_controller_spec.rb
@@ -136,5 +136,41 @@ RSpec.describe StagesController, type: :controller do
         expect(deserialize_response(response)[:error]).to eq('The state attribute may only be changed to finished')
       end
     end
+
+    context 'when a tie around the advancing cutoff still needs a decider match' do
+      let(:group_stage) do
+        create(:group_stage, tournament: create(:tournament, teams_count: 0), group_count: 0)
+      end
+
+      before do
+        tournament = group_stage.tournament
+        tournament.update!(playoff_teams_amount: 1, instant_finalists_amount: 1, intermediate_round_participants_amount: 0)
+        group = create(:group, stage: group_stage, match_count: 0, number: 1)
+        group_stage.groups = [group]
+        team_a = create(:team, tournament: tournament, name: 'A')
+        team_b = create(:team, tournament: tournament, name: 'B')
+        create(:group_match, group: group, state: :finished).tap do |match|
+          create(:match_score, match: match, team: team_a, points: 2)
+          create(:match_score, match: match, team: team_b, points: 2)
+        end
+        score_a = create(:group_score, group: group, team: team_a, group_points: 7, scored_points: 4, received_points: 1)
+        score_b = create(:group_score, group: group, team: team_b, group_points: 7, scored_points: 4, received_points: 1)
+        GroupStageService.send(:recalculate_position_of_group_scores!, [score_a, score_b]).each(&:save!)
+
+        apply_authentication_headers_for group_stage.owner
+        put :update, params: { id: group_stage.to_param }.merge(finished)
+      end
+
+      it 'returns unprocessable entity' do
+        expect(response).to have_http_status(:unprocessable_entity)
+      end
+
+      it 'returns a helpful decider error' do
+        body = deserialize_response(response)
+        expect(body[:error]).to eq('Playoffs cannot be generated yet because a decider match is required for an advancing place')
+        expect(body[:blocking_ties].size).to eq(1)
+        expect(body[:blocking_ties].first[:team_names]).to eq(%w[A B])
+      end
+    end
   end
 end
diff --git a/spec/factories/matches.rb b/spec/factories/matches.rb
index 6b9facd..9e10eb0 100644
--- a/spec/factories/matches.rb
+++ b/spec/factories/matches.rb
@@ -44,6 +44,10 @@ FactoryBot.define do
   factory :group_match, class: Match do
     group
     position { 0 }
+
+    trait :decider do
+      decider { true }
+    end
     factory :filled_group_match do
       transient do
         match_scores_count { 2 }
diff --git a/spec/models/group_score_spec.rb b/spec/models/group_score_spec.rb
index 7a9490b..2e4e184 100644
--- a/spec/models/group_score_spec.rb
+++ b/spec/models/group_score_spec.rb
@@ -69,7 +69,10 @@ RSpec.describe GroupScore, type: :model do
       expect(group_score_a.comparison_reason_against(group_score_b)).to eq(
         resolved_by: :group_points,
         tied: false,
-        direct_comparison_result: nil
+        direct_comparison_result: nil,
+        hidden_points_result: :not_played,
+        direct_comparison_match_id: nil,
+        decider_match_id: nil
       )
     end
 
@@ -83,7 +86,10 @@ RSpec.describe GroupScore, type: :model do
       expect(group_score_a.comparison_reason_against(group_score_b)).to eq(
         resolved_by: :direct_comparison,
         tied: false,
-        direct_comparison_result: :won
+        direct_comparison_result: :won,
+        hidden_points_result: :not_played,
+        direct_comparison_match_id: group.matches.last.id,
+        decider_match_id: nil
       )
     end
 
@@ -97,7 +103,31 @@ RSpec.describe GroupScore, type: :model do
       expect(group_score_a.comparison_reason_against(group_score_b)).to eq(
         resolved_by: :tie,
         tied: true,
-        direct_comparison_result: :draw
+        direct_comparison_result: :draw,
+        hidden_points_result: :not_played,
+        direct_comparison_match_id: group.matches.last.id,
+        decider_match_id: nil
+      )
+    end
+
+    it 'falls back to hidden points when direct comparison is still tied' do
+      group_score_b.update!(group_points: 6)
+      create(:group_match, group: group, state: :finished).tap do |match|
+        create(:match_score, match: match, team: team_a, points: 2)
+        create(:match_score, match: match, team: team_b, points: 2)
+      end
+      create(:group_match, group: group, state: :finished, decider: true).tap do |match|
+        create(:match_score, match: match, team: team_a, hidden_points: 3)
+        create(:match_score, match: match, team: team_b, hidden_points: 1)
+      end
+
+      expect(group_score_a.comparison_reason_against(group_score_b)).to eq(
+        resolved_by: :hidden_points,
+        tied: false,
+        direct_comparison_result: :draw,
+        hidden_points_result: :won,
+        direct_comparison_match_id: group.matches.reject(&:decider?).last.id,
+        decider_match_id: group.matches.select(&:decider?).last.id
       )
     end
   end
diff --git a/spec/routing/matches_routing_spec.rb b/spec/routing/matches_routing_spec.rb
index f0f4806..9b5918d 100644
--- a/spec/routing/matches_routing_spec.rb
+++ b/spec/routing/matches_routing_spec.rb
@@ -7,5 +7,9 @@ RSpec.describe MatchesController, type: :routing do
     it 'routes to #show' do
       expect(get: '/matches/1').to route_to('matches#show', id: '1')
     end
+
+    it 'routes nested group matches to #create' do
+      expect(post: '/groups/1/matches').to route_to('matches#create', group_id: '1')
+    end
   end
 end
diff --git a/spec/services/group_stage_service_spec.rb b/spec/services/group_stage_service_spec.rb
index eec7149..1cf60fb 100644
--- a/spec/services/group_stage_service_spec.rb
+++ b/spec/services/group_stage_service_spec.rb
@@ -246,6 +246,7 @@ RSpec.describe GroupStageService do
         resolved_by: 'direct_comparison',
         compared_with_team_id: team_b.id,
         direct_comparison_result: 'won',
+        hidden_points_result: 'not_played',
         tied: false,
         needs_decider_match: false
       )
@@ -253,6 +254,7 @@ RSpec.describe GroupStageService do
         resolved_by: 'direct_comparison',
         compared_with_team_id: team_a.id,
         direct_comparison_result: 'lost',
+        hidden_points_result: 'not_played',
         tied: false,
         needs_decider_match: false
       )
@@ -277,12 +279,14 @@ RSpec.describe GroupStageService do
       expect(GroupStageService.ranking_decision_for(score_a)).to include(
         resolved_by: 'tie',
         direct_comparison_result: 'draw',
+        hidden_points_result: 'not_played',
         tied: true,
         needs_decider_match: true
       )
       expect(GroupStageService.ranking_decision_for(score_b)).to include(
         resolved_by: 'tie',
         direct_comparison_result: 'draw',
+        hidden_points_result: 'not_played',
         tied: true,
         needs_decider_match: true
       )
@@ -301,15 +305,46 @@ RSpec.describe GroupStageService do
       expect([score_a.position, score_b.position, score_c.position, score_d.position]).to eq([1, 2, 3, 3])
       expect(GroupStageService.ranking_decision_for(score_c)).to include(
         resolved_by: 'tie',
+        hidden_points_result: 'not_played',
         tied: true,
         needs_decider_match: false
       )
       expect(GroupStageService.ranking_decision_for(score_d)).to include(
         resolved_by: 'tie',
+        hidden_points_result: 'not_played',
         tied: true,
         needs_decider_match: false
       )
     end
+
+    it 'uses the decider hidden points to resolve a cutoff tie' do
+      tournament.update!(playoff_teams_amount: 1, instant_finalists_amount: 1, intermediate_round_participants_amount: 0)
+
+      create(:group_match, group: group, state: :finished).tap do |match|
+        create(:match_score, match: match, team: team_a, points: 2)
+        create(:match_score, match: match, team: team_b, points: 2)
+      end
+      create(:group_match, group: group, state: :finished, decider: true).tap do |match|
+        create(:match_score, match: match, team: team_a, hidden_points: 5)
+        create(:match_score, match: match, team: team_b, hidden_points: 3)
+      end
+
+      score_a = create(:group_score, group: group, team: team_a, group_points: 7, scored_points: 4, received_points: 1)
+      score_b = create(:group_score, group: group, team: team_b, group_points: 7, scored_points: 4, received_points: 1)
+      score_c = create(:group_score, group: group, team: team_c, group_points: 3, scored_points: 2, received_points: 3)
+      score_d = create(:group_score, group: group, team: team_d, group_points: 0, scored_points: 1, received_points: 7)
+
+      GroupStageService.send(:recalculate_position_of_group_scores!, [score_a, score_b, score_c, score_d]).each(&:save!)
+
+      expect([score_a.position, score_b.position, score_c.position, score_d.position]).to eq([1, 2, 3, 4])
+      expect(GroupStageService.ranking_decision_for(score_a)).to include(
+        resolved_by: 'hidden_points',
+        direct_comparison_result: 'draw',
+        hidden_points_result: 'won',
+        tied: false,
+        needs_decider_match: false
+      )
+    end
   end
 
   describe '#get_advancing_teams' do