She became the World No. 1 for the first time on July 8, 2002, and regained this ranking for the sixth time on February 18, 2013, becoming the oldest world no. 1 player in WTA's history. Williams is also regarded by some experts and former tennis players to be the greatest female tennis player in history. She is the only female player to have won over $60 million in prize money, and is the reigning US Open, WTA Tour Championships and Olympic ladies singles champion.
Williams holds the most Major singles, doubles, and mixed doubles titles combined amongst active players, male or female. Her record of 33 Major titles puts her seventh on the all-time list: 18 in singles, 13 in women's doubles, and 2 in mixed doubles
She is the most recent player, male or female, to have held all four Grand Slam singles titles simultaneously ('02–'03), and the fifth woman ever to do so. She is also the most recent player together with her sister Venus Williams to have held all four Grand Slam women's doubles titles simultaneously ('09–'10).