One-game Playoff

A one-game playoff, sometimes known as a pennant playoff or play-in game, is a tiebreaker in certain sports—usually but not always professional—to determine which of two teams, tied in the final standings, will qualify for a post-season tournament. Such a playoff is either a single game or a short series of games (such as best-2-of-3).

This is distinguished from the more general usage of the term "playoff", which refers to the post-season tournament itself.