Petkovic pulls out of Australian Open

Melbourne: Germany's top-ranked tennis player Andrea Petkovic has pulled out of next week's Australian Open grand slam tournament with a stress fracture, she said yesterday.

"Sorry to announce that I had to withdraw from the Australian Open with a lower back stress fracture," the 24-year-old said in a post on her Twitter account.

"Going back home, will miss my Aussie fans!"

The world number 10 suffered a knee injury in October, but returned to play her first WTA tournament at Brisbane last week where she made the quarter-finals.

She was dumped out of the Sydney International in the second round on Tuesday by Pole Agnieszka Radwanska in straight sets. Bosnia-born Petkovic, famous on tour for her post-match victory dances, upset Maria Sharapova on the way to the quarter-finals at Melbourne Park last year where she was stopped by eventual finalist Li Na.

Health reasons

The tenth seed's withdrawal came shortly after seven-times grand slam winner Venus Williams pulled out, also citing health reasons.

Williams has been receiving treatment for Sjogren's syndrome, an auto-immune disease that causes fatigue and joint soreness.

A number of other contenders in the women's draw head into the year's first grand slam under injury clouds, including champion Kim Clijsters.

Clijsters has a strained hip muscle, and fellow former world number one Serena Williams twisted her ankle in Brisbane last week.