MELBOURNE, Australia ? Down four match points and hobbling on her injured left ankle, defending champion Kim Clijsters somehow rallied for a dramatic 4-6, 7-6 (6), 6-4 win over Li Na at the Australian Open on Sunday.
Clijsters was in pain from the ankle she twisted in the seventh game. Li was just a bundle of nerves. The French Open champion failed to serve out the fourth-round match at 5-4 in the second set, but then led 6-2 in the tiebreaker. Again Clijsters refused to yield.
"I said in my mind, keep fighting," Clijsters said. "You never know what happens on the other side of the court."
Rafael Nadal and Roger Federer stayed on course for a semifinal meeting in matches either side of Clijsters's win at Rod Laver Arena. Federer ended the run of Australian teenager Bernard Tomic 6-4, 6-2, 6-2, while Nadal won in straight sets too, beating fellow Spaniard Feliciano Lopez 6-4, 6-4, 6-2.
Top-seeded Caroline Wozniacki ended the day's play with a 6-0, 7-5 win over Jelena Jankovic and will next play Clijsters.
Li's best chance to win the match ? and gain revenge for her three-set loss to Clijsters in last year's final ? came on her fourth match point.
Clijsters played a poor drop shot, giving her opponent the chance to put the ball into the open court. Instead, Li tentatively hit the ball almost straight back to Clijsters, who sent up a perfect lob that dropped just inside the baseline.
"Of course I was nervous," Li said. "If you're nervous, you could not think too much, right?"
Clijsters won six straight points to take the tiebreaker and the first four games of the deciding set.
"I'm not saying that that forehand drop shot was a good choice, but you make decisions. Luckily, that one turned out OK," Clijsters said. "I think she was a little bit lost or maybe a little bit confused at that time."
Clijsters then overcame a wobble of her own, losing her serve at 5-2 in the third set, before finally closing out the fourth-round match on her second match point.
Li broke down in tears at the end of her post-match news conference.
"Maybe 6-2 up in the tiebreak I was a little bit shocking," she said.
Clijsters was hurt in the first set while serving at 3-all and 30-all. As she hit a forehand, her left foot got stuck on the surface and the ankle twisted awkwardly.
She got up to finish the point but then immediately called for the trainer and had the injury strapped.
Clijsters' movement was clearly slowed when she resumed but, playing in her last Australian Open before quitting tennis at the end of the season, she said she didn't want to bow out in Melbourne with a retirement.
"I knew if I could just try to let the medication sink in or if I could get through the first 20 minutes, half hour, I think the pain would go away a little bit and then maybe with the adrenaline I could just fly through it."
The injury seemed to affect Li just as much. The 29-year-old, who won last year's French Open to become the first player from China to win a Grand Slam singles title, looked increasingly stressed as the match progressed.
After 2 hours, 23 minutes, she netted a backhand to put Clijsters through to the quarterfinals. The Belgian said she was hopeful her ankle would hold up after ice treatment.
Federer hasn't lost to a teenager since 2006 and that run continued Sunday as he disappointed the home crowd with a comprehensive win over the 19-year-old Tomic.
Tomic had beaten seeded players Fernando Verdasco and Alexandr Dolgopolov in earlier rounds, but Federer was a step-up in class. The 16-time Grand Slam champion broke six times as he set up a quarterfinal against 11th-seeded Argentine Juan Martin del Potro.
"I thought I played a really good match," said Federer, through to his 31st straight Grand Slam quarterfinal. "I knew I had to. Anything else wouldn't have done the job tonight."
Nadal was almost as convincing in his win over Lopez. The 2009 champion had his right knee heavily strapped and had his left ankle taped after three games of the first set but afterward said he was "fine."
Nadal plays Tomas Berdych next, hoping to avoid a third straight quarterfinal loss in Melbourne. Defending the title in 2010, the Spaniard retired with a knee injury against Andy Murray. A year ago, he was hampered by a hamstring problem in a straight-sets loss to David Ferrer.
"Hopefully not happen this time," Nadal said. "I had a bad experience last two years here. It's tough have to go out of a tournament like Australia in quarterfinals."
Berdych beat Nicolas Almagro of Spain 4-6, 7-6 (5), 7-6 (3), 7-6 (2). Former U.S. Open champion Del Potro easily defeated Philipp Kohlschreiber of Germany 6-4, 6-2, 6-1.
Berdych was booed by the crowd at Hisense Arena after he refused to shake hands with Almagro. The sixth-seeded Czech was upset that Almagro had hit the ball straight at him while he was at the net during the fourth set.
Wozniacki advanced with a chance of keeping her top ranking by beating former No.1-ranked Jankovic.
"My confidence is high, my fitness is good, my play is improving and I'm very positive," said Wozniacki, who is looking for her first Grand Slam title.
Victoria Azarenka was the first player to reach the quarterfinals when she beat Iveta Benesova 6-2, 6-2. The third-seeded Belarusian is yet to drop a set at the tournament and will next meet eighth-seeded Agnieszka Radwanska.
With the win, 22-year-old Azarenka stayed in the hunt for the No. 1 ranking. Petra Kvitova and Maria Sharapova can also claim the top spot from Wozniacki.
"I would be a liar if I said I didn't care about it," Azarenka said.