The tie-break is not employed in the final set, so that the set must be won by the player or team has won two more games than the opponent. This rule is true for all of the Grand Slam tournaments, except one. Name it.

The US Open is the only Grand Slam tournament that uses a tie-break in the final set. Since 1970, the US Open has employed a tie-break at 6-6 in the final set, unlike Wimbledon, French Open, and Australian Open which require players to win by two games in the final set (though Wimbledon has since introduced a special tie-break at 12-12). This makes the US Open unique among the majors in its final-set format.