Serena Williams fought back against No. 1-ranked Victoria Azarenka Sunday night, to win her fourth U.S. Open title.

Williams, who hadn't dropped a set in the tournament until she met Azarenka in the finals, was two points away from losing to 23-year-old but eventually triumphed in the third set to win 6-2, 2-6, 7-5. on Sunday night for her fourth championship at Flushing Meadows and 15th Grand Slam title overall.

With the win Williams became the firt women's tennis player to cross $40 million in earnings. With this U.S. Open singles title and her third round doubles loss, her on-court career earnings are now $40,090,142.

"I honestly can't believe I won. I really was preparing my runner-up speech, because I thought, 'Man, she's playing so great,' " Williams said during the trophy presentation after the 2-hour, 18-minute match, adding: "I'm really shocked."