"Game, set, match" is the phrase used by tennis players and officials to indicate that the final point of a match has been played. In a competitive tennis match, a player must win a minimum of 4 points with at least a 2-point advantage in order to win a game.
|POINTS||SET 1||SET 2||SET 3|
In the example above, Player A is one point away from winning the game in the third set. This is called match point. If Player A wins this game, the third set is over. As a result of winning that game, they would have won the set 6-4. In a two out of three set match, Player A wins the match if another game is won. If that were to happen, the official would say "game, set, match" to indicate that Player A officially won the match.