- Serena Williams withdraws from the Brisbane International due to an ankle injury
- The American had earlier managed to defeat Serbia's Bojana Jovanovski 6-2 6-4
- The 13-time grand slam champion hopes to be fit for this month's Australian Open
- Williams has won the Melbourne event five times, a record in the Open era
Former world number one Serena Williams has withdrawn from the Brisbane International tournament in Australia after suffering an ankle injury in Wednesday's third-round victory over Bojana Jovanovski.
However, the American hopes it will not stop her from competing at this month's Australian Open, an event that the 13-time grand slam champion has won five times -- a record in the post-1968 Open era.
The world No. 12 sustained the injury while serving for the match at 5-3 in the second set of her clash with Jovanovski at the Pat Rafter Arena.
The Serbian broke to keep the contest alive, but fourth seed Williams responded to earn a 6-2 6-4 win before the results of a scan forced her to exit the Queensland event.
"I'm disappointed to have to pull out of the Brisbane International," the 30-year-old Williams told the tournament's official website.
"I have been to hospital and it has been confirmed that I have a left ankle sprain that I probably shouldn't play on. I'm going to take a couple of days off, not too many, and see how I feel. I'm still hopeful of playing the Australian Open."
Williams was playing in her first event since losing to Samantha Stosur in the final of the U.S. Open in September, when she was fined $2,000 for verbally abusing the match umpire.
The Michigan native has been plagued by injury in recent years, having twice undergone foot surgery after stepping on a piece of glass in July 2010 and then suffering blood clots on both lungs.
"It was such an unexpected end to the tournament," she said. "I didn't expect to be getting an MRI today. I've had a great time here in Brisbane -- the tournament is great, the fans are fantastic and hopefully I'll see them again next year."
Slovakia's Daniela Hantuchova is guaranteed a place in the last four as a result of Williams' withdrawal, having beaten American Vania King 4-6 6-2 6-3 in the third round on Tuesday.
Jovanovski's fellow Serb Jelena Jankovic reached the quarterfinals after the former world number one earned a straight-sets 6-3 6-2 win against Russian qualifier Nina Bratchikova.
Jankovic next faces Italian third seed Francesca Schiavone, who defeated Kazakhstan's Galina Voskoboeva on Tuesday.
Estonia's Kaia Kanepi set up a last-eight clash with German second seed Andrea Petkovic after cruising past Russian No. 7 Anastasia Pavlyuchenko 6-0 6-3.
Elsewhere on the WTA Tour, top seed Sabine Lisicki battled the elements to record a hard-fought 7-6 (7-3) 3-6 6-3 success against fellow German Mona Barthel in second round of the ASB Classic in Auckland, New Zealand.
A 90-minute rain delay disrupted the opening set, which Lisicki eventually won in a tie-break, and the world No. 15 clinched the decider in a match which saw both players surrender seven breaks of serve.
Lisicki next faces compatriot Angelique Kerber, who upset fifth seed Julia Gorges 6-2 6-3 in another all-German encounter.
Chinese second seed Peng Shuai crashed out of the hard-court event, losing 6-4 6-3 to the Czech Republic's Lucie Hradecka.
The 26-year-old Hradecka will face Peng's compatriot Zheng Jie in the last eight, after the world No. 48 eliminated Romanian eighth seed Monica Niculescu 6-0 6-2.
Russian third seed Svetlana Kuznetsova thrashed American Christina McHale 6-1 6-1 to set up a clash with Italy's Sara Errani -- who beat 2010 champion and 2011 runner-up Yanina Wickmayer. The Belgian seventh seed lost 4-6 6-1 6-1 in her second match since an injury retirement at September's U.S. Open.
Fourth seed Flavia Pennetta beat Britain's Elena Baltacha 6-4 6-2 to set up a quarterfinal with Russia's Elena Vesnina, who eliminated the 2010 runner-up's fellow Italian Roberta Vinci 6-3 6-4.
Meanwhile, the United States' hopes of retaining the Hopman Cup ended after a 3-0 Group A loss to the Czech Republic.
World No. 2 and Wimbledon champion Petra Kvitova got the Czechs off to the perfect start by beating Bethanie Mattek-Sands 6-2 6-1, then Tomas Berdych defeated top-ranked American men's player Mardy Fish.
World No. 7 Berdych and Kvitova made it a clean sweep for the Czechs by taking the dead doubles rubber 6-3 7-5. The result put the Czechs in a strong position to qualify for the final ahead of their last group match against Denmark on Friday.
The Danish pair of world No.1 Caroline Wozniacki and Frederik Nielsen lost 2-1 to Bulgaria's Tsvetana Pironkova and Grigor Dimitrov.
Wozniacki defeated Pironkova 7-5 4-6 6-2 in the opening rubber, before Dimitrov leveled for Bulgaria with a 7-6 6-2 win over Nielsen. Bulgaria won the deciding doubles rubber 6-3 7-5, but both teams can still qualify for Saturday's final.