In a knock-out tournament featuring 21 teams, the structure is designed such that each match eliminates one team. The tournament progresses until there is only one remaining team, the winner. To determine the winner in this type of competition, there are 20 matches as each match eliminates one team from the tournament, leaving only one team standing.
Additionally, a match is typically held to determine the third place finisher, which adds 1 more match to the total count. This match is played between the two teams that lose in the semi-final stages of the tournament. Therefore, the total number of matches played in the tournament is:
20 matches (to determine the winner) + 1 match (for third place) = 21 matches.
In conclusion, for a knock-out tournament with 21 teams, a total of 21 matches are played to decide both the winner and the third-place finisher, ensuring that every team is given a fair opportunity to compete for the top spots.