noun
championship deciding match; title decider
Used in sports contexts for a match that determines the overall winner of a tournament or league, often a final or playoff.
今夜の優勝決定戦は全国放送される。
Tonight's championship deciding match will be broadcast nationwide.
両チームは優勝決定戦で対戦する。
The two teams will face each other in the title decider.
Compound of 優勝 (championship) + 決定 (decision) + 戦 (match).