'Twinkle toes' stuns angry Williams-US Open final.

Australia's Samantha Stosur reacts with joy after pulling off a straight sets win over an overwhelming favourite Serena Williams of USA in the US Open women's final in New York on Sunday.

Even before she began berating the chair umpire, things were not going well for Serena Williams in the US Open final.

Her strokes were off-target. Her opponent, Sam Stosur, was playing better than ever. And Williams' deficit was growing more and more daunting.

In the end, Stosur's powerful shots and steadiness allowed her to beat Williams 6-2, 6-3 in a surprisingly lopsided upset for her first Grand Slam title. Stosur left the court as the US Open champion; Williams' night ended with her facing possible disciplinary action.

“I'm still kind of speechless. I can't actually believe I won this tournament,” Stosur said later, the silver US Open trophy sitting a few feet away. “I guess to go out there and play the way I did is obviously just an unbelievable feeling, and you always hope and you want to be able to do that, but to actually do it, is unbelievable.”The ninth-seeded Stosur became the first Australian woman to win a major championship since Evonne Goolagong Cawley at Wimbledon in 1980. Stosur received a text from the former player that read: “Twinkletoes, you finally have got what you deserved.”

The sentiment was echoed by Prime Minister Julia Gillard, who phoned Stosur to personally congratulate her after the triumph.Only 2-9 in tournament finals before beating Williams, Stosur made the US Open the third consecutive Grand Slam tournament with a first-time women's major champion, after Li Na at the French Open, and Petra Kvitova at Wimbledon.

This was only the 27-year-old Stosur's third title at any tour-level event, and what a way to do it. She took advantage of Williams' so-so serving and finished with 12 unforced errors to Williams' 25.

Most of all, Stosur avoided being distracted by the bizarre events that unfolded in the second set's opening game. Asderaki ruled that Williams' mid-point cry of “Come on!” hindered Stosur's ability to complete that point and awarded it to Stosur, putting her ahead 1-0.

Williams went over to talk to Asderaki, saying, “I'm not giving her that game.”Spectators began jeering, delaying the start of the next game as both players waited for the noise to subside.“It was probably the loudest I ever felt a crowd in my whole entire life. You're right in the middle of it. It was definitely a quite overwhelming feeling,” Stosur said. “But once I hit that next ball in the court and started playing again, I felt settled. I guess it definitely could have been the big, pivotal point in the match.”The truth is, the outcome never really appeared to be in doubt.

Even Williams acknowledged as much.“She was cracking 'em today,” said Williams, whose five games matched her lowest total in 240 Grand Slam matches. “She definitely hit hard and just went for broke.”

Stosur was playing in only her second major finalshe was the runner-up at the 2010 French Openwhile Williams was in her 17th.

“I felt like I was definitely the underdog,” Stosur said.For all of her edges in experience, Williams was the one who started a bit shakily. She was back in action less than 18 hours after winning her semifinal over No. 1 Caroline Wozniacki on Saturday night, and Williams' game was sleepy.

“It was a little bit of a tough turnaround, but I don't think it would have made a difference today,” said Williams, who said she didn't fall asleep until after 4 a.m. “I just probably should have been lighter on my toes and move in a little faster.”

Her serveusually one of her top shotswas problematic, slower and less accurate than usual: Only three of her initial 14 first serves landed in, and they hovered around 100 mph. Told she'd put 35 percent of her first serves in play during the first set, Williams replied: “Wow. That's not so good.”

Williams pushed a backhand long to get broken and fall behind 2-1. She flubbed another backhand to lose serve and make it 5-2. When Stosur smacked a forehand winner moments later, she had taken 12 points in a row and owned the first set.

That was the first set Williams had lost in seven matches during this US Open, a run that included four victories over women ranked in the top 20. She said her poor play Sunday is what made her so excited when she hit the forehand that led to all the commotion.

“It was beautiful. I hit it, like, right in the sweet spot,” Williams said. “It was a good shot, and it was the only good shot I think I hit. I was like, 'Woo-hoo!”'That moment of joy didn't last long.

Entering the final, Williams was 18-0 on hard courts this season, a full-throttle comeback after missing nearly a year because of health scares, including cuts on her feet from glass at a restaurant, two foot operations, clots in her lungs and a gathering of blood beneath the skin of her stomach.

She was ranked 175th after a fourth-round exit at Wimbledon, but hadn't lost since then until Sunday and was seeded 28th at the U.S. Open.Stosur dealt with her own health issues that could have sidetracked her career, and she became the oldest US Open champion since Martina Navratilova was 30 in 1987.

Once a doubles specialistshe's won Grand Slam titles in women's and mixed Stosur only once got past the third round in singles at a major tournament before reaching the 2009 semifinals at the French Open.Her game has improved dramatically since she returned to the tour in April 2008 after about nine months away while recovering from Lyme disease, a tick-born illness that can affect a person's joints and nervous system. She was ranked 149th two years ago; on Monday, she'll rise to No. 7.

“It kind of made me open my eyes more that you don't necessarily always get a second chance,” Stosur said. “I wanted to take every opportunity I had, and I have now been able to fulfill that.”