For women,it is the best of 3 sets,the player has to win 2 sets to claim the match, irrespective of whether its a Grand Slam or any other tournament. In Men tennis on Grandslams (so also in Australian Open) it is 3 won sets.. so it can be 3,4 or 5 sets in a match. But during the ATP tour it is the same as women.. so 2 won sets.. In women on Grandslams and also during WTA tour it is 2 won sets..