Serena Williams
Serena Williams is expected to win on Saturday. Reuters

On Sunday, tennis superstar Serena Williams, 30, beat the No. 1-ranked female player in the world, Victoria Azarenka, 23, and became the oldest U.S. Open champion in nearly four decades.

"I honestly can't believe I won. I was really prepared for my runner-up speech, because she was playing so great. I'm really shocked right now," Williams said after the ferocious three-set match.

Williams also spoke with the Associated Press about dating, after rival Maria Sharapova revealed during the Open that her engagement to basketball player Sasha Vujacic was off. "If I'm in a relationship, I'm fine; I do well. But I feel like when I'm out, I'm angry and I do even better," Williams said with a laugh. "I don't know what's better for me. It's a win-win situation."

During earlier rounds of this U.S. Open, it was speculated that Williams was back with ex-boyfriend Common, after he cheered her on during the third-round women's doubles match. As Common, 40, entered the stadium, he went straight to Williams' mother, Oracene Price, and her friends and family, and sat with them to watch the match.

During the game, which ended in a loss for the sisters, 6-1, 6-4, as they failed to find their rhythm, Common clapped enthusiastically for Serena and Venus when they won set points.

After the game, Common warmly embraced Price before exiting Louis Armstrong Stadium.

But earlier this year, Williams told Celebuzz, "I have given up on dating. It just hasn't worked out well for me ... I just have to remove myself from that atmosphere for about the next decade or so."