MELBOURNE, AUSTRALIA (AP) - The mixed doubles draw was a little more star-studded than usual at the Australian Open this year, at least until Andy Roddick's hamstring injury.
Roddick and Serena Williams had entered the draw to get practice in case they decide to play together at the 2012 London Olympics, but Roddick hurt his leg and withdrew from his second-round singles match on Thursday night.
After seeing Roddick's injury, Serena tweeted: "Oh no my dubs partner!!!!! :("
There are a few other intriguing partnerships left in the draw, including the Japanese team of Kimiko Date-Krumm and Kei Nishikori and the Indian duo of Sania Mirza and Mahesh Bhupathi.
With three top men's doubles players, India is considered a gold-medal threat in the mixed competition. The only question is who will play with Mirza in London.
Though representing different nations, former No. 1 Jelena Jankovic of Serbia is also partnering with Australian teen sensation Bernard Tomic.
Two players that definitely won't be playing together in London are Roger Federer and Martina Hingis. Federer asked Hingis last year about teaming up for Switzerland, but Hingis declined _ a decision she confirmed Thursday at Melbourne Park.
"We talked at the end of the season," Hingis told The Associated Press. "I haven't played for four years. He has to concentrate on singles and (men's) doubles and I think it's better that way."
THEM'S THE BREAKS: Milos Raonic's perfect serving start to the year has finally been broken.
The big-serving Canadian began the season by winning all 48 of his service games in four matches at Chennai, India _ the first player to win a title without dropping serve since Roger Federer did it in Halle in 2008. He served 76 aces and saved all 14 break points he faced.
Raonic also was perfect on serve in his first-round match at Melbourne Park. However, on Thursday, the streak ended when Germany's Philipp Petzschner broke him twice in the second round. Raonic at least came away with the win, 6-4, 5-7, 6-2, 7-5.
The 21-year-old later acknowledged he was a little tight during the match.
"It's always tough to close out a match. Especially for me a big part of closing out matches is my serve. I don't think in the first game I put in any first serves," Raonic said.
Raonic has still won 79 of 81 service games to start the season, for an impressive 97.5 percent.
TEED OFF: Ana Ivanovic and Caroline Wozniacki have both been trying to pick up tips from their golfer boyfriends. Neither is having much luck.
"My golf is not so good," said Ivanovic, who is dating No. 7-ranked Adam Scott of Australia. "I can hit the ball sometimes. I putt good, though. I can do that."
Wozniacki, whose boyfriend is U.S. Open champion Rory McIlroy, said Wednesday she had been on the course a few times with the Northern Irishman, but "once I'm out there alone and have to start playing, it goes right and left and up and down."
They'll keep their day jobs. Ivanovic joined Wozniacki in the third round Thursday after a 6-2, 6-3 win over Michaella Krajicek of the Netherlands.
She dropped one point on serve in the first set _ and that was a double-fault.
Scott, an eight-time winner on the PGA Tour, has been courtside for both of Ivanovic's matches this week. He'll be there when she plays Vania King of the United States in the third round on Saturday.
"He's going to stay. It's great to have that support," said Ivanovic, who reached the Australian Open final in 2008 before winning her only Grand Slam title at Roland Garros four months later.
The 24-year-old Ivanovic's ranking has fluctuated since then, and several coaches have come and gone. Ivanovic has been working with British coach Nigel Sears since June.
"I feel really comfortable in the environment I have now," she said. "I think that's been the biggest change. It was a tough one. But I really feel it's helped my game a lot, and my mental side as well. It's been great."
AP Sports Writer Caroline Cheese contributed to this report.