title match; championship game; struggle for supremacy
Refers to a decisive contest for a championship or top position, often in sports or competitions.
Both teams will face off in the championship game tomorrow.
This tournament is a struggle for supremacy to determine the world's best.
優勝決定戦 is a more descriptive phrase for a match that decides the winner, whereas 争覇戦 is a compact compound with a slightly formal or literary tone.
Compound of 争 (そう, 'contend') + 覇 (は, 'supremacy') + 戦 (せん, 'match'). The exact historical derivation is uncertain, but the spelling is conventionally associated with the meaning of a contest for dominance.