MELBOURNE, Australia (AP) - Venus Williams lasted just seven points in her third-round match Friday at the Australian Open, forced to withdraw due to injury from a Grand Slam singles match for the first time in her career.

After losing the first game to Andrea Petkovic of Germany and trailing in the second, Williams stretched to her right to return a serve, hit the ball and then cried out in pain, clutching toward her stomach on her right side. It was soon clear that she couldn't continue.

"Obviously I just couldn't play," Williams said. "I couldn't move, it was too painful."

Her right thigh was already heavily bandaged from an injury she sustained in the first set of her second-round match Wednesday, when she beat Sandra Zahlavova in three sets. Afterward, Williams said the injury was in her "psoas" muscle, which flexes the hip and spinal column.

"The last 48 hours, I just did as much pain management as I could," she said. "A lot of times when you play, you get that adrenalin and that blocks pain. I just didn't get enough of that today. I was hoping for some magic that I could recover."

Williams, 30, waved to the Rod Laver Arena crowd and appeared to be on the verge of tears as she walked off the court. Her younger sister, defending champion Serena, didn't even make it to Melbourne Park because of a foot injury.

"It's super disappointing because this is just not how I envisioned my Australian Open being," Venus Williams said. "But I have peace of mind that I really gave more than my best to be out there."

"I'm just going to focus obviously on getting healthy and coming back, because I love tennis and I've got a lot of great tennis in me. I love my job, so no end in sight."

Petkovic was surprised by the sudden end to the match.

"I feel very weird about how the things went," said Petkovic. "It's a pity, and I feel very sorry. I just hope she gets better - she's such a great champion."

Justine Henin departed the tournament a lot sooner than she expected, too, but No. 1-seeded Caroline Wozniacki is still around, providing entertainment on and off the court.

Henin, the 2010 finalist, was beaten by two-time Grand Slam winner Svetlana Kuznetsova 6-4, 7-6 (8) in a mild third-round upset, while Roger Federer, Novak Djokovic, Andy Roddick and Maria Sharapova all advanced.

Wozniacki provided as much fanfare in her post-match media conference as she did during her 6-4, 6-3 win over Dominika Cibulkova.

Pretending to be irritated at being considered "boring" by some critics, she came prepared with a monologue to answer any question that might be asked about the match, and then some.

"I always gave the same answers," Wozniacki said. "I find it quite funny because I always get the same questions, so I'm just going to start with the answer."

What transpired was one of the funniest schticks ever to grace the tiered news conference room under Rod Laver Arena. Once she got the usual match comments out of the way, Wozniacki had a chance to be asked about global warming, her prowess on the piano, the game of cricket and what she's looking for in a boyfriend.

"Hopefully this was a little bit different than usual, and now you can maybe give me some questions that are a little bit more interesting," the 20-year-old Wozniacki said.

Henin and Kuznetsova didn't have much fun following Wozniacki on the court.

Kuznetsova twice had chances to serve out the match but Henin broke her both times.

Henin was only weeks into a comeback from a career break from the tour when she lost the final last year to Serena Williams, the third time in four appearances that she'd reached the championship match at Melbourne. Her comeback season was derailed when she injured her right elbow at Wimbledon and didn't play again in 2010.

"There's no excuse, even if I know I'm not at 100 percent, she was better than me today," Henin said in remarks translated from French. "I made way too many errors."

It was Henin's first loss in a major to Kuznetsova, the former French and U.S. Open champion, and her worst run at a Grand Slam event since Wimbledon in 2005.

Sharapova, who won the 2008 Australian women's title, struggled to a 4-6, 6-4, 6-4 win over Julia Goerges of Germany. French Open champion Francesca Schiavone of Italy also won, beating Monica Niculescu of Romania 6-0, 7-6 (2).

No. 9 Li Na of China, who reached the semifinals last year before losing in two tiebreaker sets to eventual champion Serena Williams, advanced 6-2, 6-1 over Barbora Zahlavova Strycova.

Schiavone and Kuznetsova, who will play each other in the fourth round, had what Kuznetsova called a misunderstanding after a Fed Cup match won by Italy over Russia.

"We didn't talk for some time, I didn't shake her hand," Kuznetsova said. "So after we spoke in the locker room ... we are completely over it. I said sorry or whatever."

Federer was back to his vintage best, beating Xavier Malisse 6-3, 6-3, 6-1. While the defending champion also won in straight sets in his opening-round match against Lukas Lacko, he was extended to five tough sets against Gilles Simon in the second round, a near five-hour match that Federer said he was he relieved to survive.

On Friday at Rod Laver Arena, there was no such drama for the second-seeded Swiss star who is chasing his fifth Australian title.

It took him 1 hour, 45 minutes to beat Malisse and earn an Open Era-record 57th match win at the Australian Open, breaking Stefan Edberg's record.

"I'm OK today, and I'm happy I was able to come through it," Federer said. "Surely it's not the easiest thing to come back after a five-setter, but I managed. I'm sure that another day of rest is going to do me good."

Federer will play Tommy Robredo, who beat Ukraine's Sergiy Stakhovsky 5-7, 6-2, 6-4, 6-2.

Roddick overcame a slow start before powering to victory with 32 aces to beat Robin Haase 2-6, 7-6 (2), 6-2, 6-2. The eighth-seeded Roddick is seeking to win his second Grand Slam nearly seven years after his first - the 2003 U.S. Open.

Haase received treatment on for an ankle early in the first set, having it heavily taped after appearing to stumble on a shot.

The trainer was back out at the end of the set for Haase, who broke Roddick's serve twice.

The Dutchman, despite the injury, made the shot of the tournament so far, chasing down a Roddick lob and hitting a flick backhand over the net while facing the back of the court. Haase won the point two shots later, only to eventually lose the match.

"He was playing great early on," Roddick conceded. "The biggest thing was just to turn it around in the second set."

Djokovic only had to play one set in the third round to advance. The 2008 Australian Open champion was leading Viktor Troicki 6-2 when his Serbian Davis Cup teammate retired due to a stomach muscle strain.

Djokovic will play No. 14 Nicolas Almagro, who beat No. 17 Ivan Ljubicic 6-4, 7-6 (8), 6-3.

"It's not really the way you want to win, especially if you're playing against one of your best friends," Djokovic said.

Ninth-seeded Fernando Verdasco advanced with a 6-2, 6-4, 6-3 win over Kei Nishikori of Japan and will play Tomas Berdych in the fourth round. The sixth-seeded Berdych beat Richard Gasquet of France 6-2, 7-6 (3), 6-2.

Stanislas Wawrinka of Switzerland beat 12th-seeded Gael Monfils 7-6 (4), 6-2, 6-3, breaking the French player in the last game. Warwinka will play Roddick in the fourth round.

LA QUINTA, California (AP) - Venezuelan rookie Jhonattan Vegas shot a 5-under 67 in windy conditions Thursday for a share of the second-round lead with Boo Weekley at the Bob Hope Classic.

Weekley had a 66 to match Vegas at 13-under 131 in the 90-hole tournament on four Palm Springs-area courses. Charles Howell III (66) and Chris Couch (65) were a stroke back.

Although Vegas, 26, bogeyed his final hole on the Nicklaus Private course, he leads the field with 17 birdies. With power and accuracy off the tee, Vegas used an improved short game to get on top early in just his fifth PGA Tour event.

"It's good to be hitting the ball well and putting well, especially on a course like these ones where you've always got a lot of birdie opportunities," said Vegas, who played at the University of Texas before excelling on the Nationwide Tour last year.

Although many pros still don't know him - Weekley had never met Vegas before they shook hands in the media tent after the second round - others already call him "Jhonny Vegas." As for the unique spelling on his birth certificate, Vegas realizes it might take a while to catch on.

"I'm happy they did it that way, because it's something different," Vegas said. "I mean, you only see one Jhonattan spelled that way, so once you see it, you know that it's me."

Vegas moved to the United States in 2002, spending nearly two years improving his English enough to attend college. He became the first Venezuelan to earn a PGA Tour card last year.

The sport is viewed with a raised eyebrow in Venezuela by President Hugo Chavez, who calls it a pastime of the rich. In hilly Caracas, the government has threatened to replaced golf courses occupying valuable areas of flat land with housing that will be less vulnerable to rain and mudslides.

"I'd love the chance to tell people about golf in Venezuela," said Vegas, whose father runs a catering company. "(Chavez) has always said that golf is for elite people, I guess, and as we all know here, it's not that way. But I guess he's got that mentality, so I really hope to sit down with him and talk to him, and tell him it's not that way."

Chavez made the cut at last week's Sony Open in Hawaii, although he didn't get to play Sunday due to the weather-shortened field. He got off the islands in time to survey all four courses in Palm Springs before Wednesday's opening round.

The Hope Classic typically is dominated by low scores, and both leaders won't be surprised if the winner of the five-round event checks in at 30 under.

"We've played two of the easier courses, me and Mr. Vegas, so it just all depends on what can happen tomorrow," Weekley said. "I feel like I can go out there and shoot 3 or 4 under, keep myself in the hunt ... and still have a chance somewhere down the line there."

Weekley birdied his final two Nicklaus holes, wrapping up a sharp round on perhaps the tournament's easiest course. The veteran changed putters after finishing in 27th-place tie at the Sony Open in Hawaii last week, and the switch already has produced remarkable results.

"To 12 feet, 15 feet, I feel like I can make it," Weekley said. "I would say for about the last year, I ain't felt that in a while. I was hoping that this would happen."

Howell shot his second 66 of the tournament, while Couch made three birdies on his final four holes. Keegan Bradley and Brian Davis are two strokes off the lead at 133, while 29 players - including David Duval and Matt Kuchar - were within five strokes of the lead.