single-round contest; one-shot game; make-or-break match
Refers to a contest, game, or gamble decided by a single round, roll, or attempt, with no second chance. Often carries a high-stakes, all-or-nothing nuance.
The final is a single-round contest; if you lose, it's over.
Let's decide the winner with a single roll of the dice.
Similar meaning, but 一発勝負 often emphasizes a single decisive action or attempt, while 一回勝負 focuses on a single round or turn in a structured contest.
Compound of 一回 (one time, one round) and 勝負 (contest, match). The derivation is straightforward; no historical uncertainty.