A one-game playoff, sometimes known as a pennant playoff, tiebreaker game or knockout 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.