A single-elimination tournament, also called a knockout or sudden death tournament, is a type of tournament where the loser of each match is immediately eliminated from winning the championship or first prize in the event. (However, it does not always mean that the defeated competitor will not participate further in the tournament (in some such tournaments, consolation or “classification” contests are subsequently held among those already defeated to determine the awarding of lesser places, for example, a Third place playoff.)

Format

Often, the number of participants in a single-elimination tournament is fixed as a power of two; for example, the Wimbledon singles championships are tournaments of 128 players. This ensures all competitors will face opponents who have previously played the same number of matches. The full schedule of pairings across all rounds (the bracket) may be allocated before the start of the tournament; or each round may be allocated at the end of the preceding round. Each successive round halves the number of competitors remaining (assuming there are no byes — see below). The round in which only eight remain at the start is generally called the quarter-final round; this is followed by the semi-final round in which only four are left, the two winners of which then meet in the final, or championship round.

In cases where the number of competitive entities at the start of the tournament is not a power of two, some competitors may receive a bye in the first round, which entitles these competitors to advance to the second round automatically without playing. Often, these byes will be awarded to the highest-rated competitors in the event as a reward for some previous accomplishment; indeed, in some American team sports – most notably football – the number of teams qualifying for the postseason tournament will be intentionally set at a number which is not a power of two, in order to provide such an advantage to a high-achieving team in the just-completed regular season.

Multiple rounds of byes are also possible: in the FA Cup, the teams in the top two league divisions enter in the third round “proper” (of eight); the two next-highest divisions’ teams will have entered in the first round; lower-division teams in one of 6 preliminary rounds.

When matches are held to determine places or prizes lower than first and second (the loser of the final-round match gaining the latter position), these typically include a match between the losers of the semifinal matches, the winner therein placing third and the loser fourth; sometimes contests are also held among the losers of the quarterfinal matches to determine fifth through eighth places (this is most commonly encountered in the Olympic Games, with the exception of boxing, where both fighters are deemed to be third place). In one scenario, two “consolation semifinal” matches may be conducted, with the winners of these then facing off to determine fifth and sixth places and the losers playing for seventh and eighth; those are used often in qualifying tournaments where only the top five teams advance to the next round; or some method of ranking the four quarterfinal losers might be employed, in which case only one round of additional matches would be held among them, the two highest-ranked therein then playing for fifth and sixth places and the two lowest for seventh and eighth.

In a tournament where more than two opponents or teams can play together at once, such as in a shootout poker tournament, players are removed when they can no longer play until one player remains from the group. This player moves on to the next round