noun
tiebreaker; playoff
A match or game played to decide a winner when scores are tied. Common in sports contexts.
試合は延長戦でも決着がつかず、同点決勝戦が行われた。
The game remained tied even after overtime, so a tiebreaker was played.
A loanword from English, often used in tennis and other sports. 同点決勝戦 is a more formal Japanese compound.
Compound of 同点 (tied score) + 決勝戦 (final match).