Fri Oct 3, 2008 5:12pm BST
MOSCOW, Oct 3 (Reuters) - World number one Serena Williams has pulled out of the Kremlin Cup with a knee injury, tournament organisers said on Friday.
"My left ankle has been bothering me since the U.S. Open and I need to take a break now to get it back to 100 percent," the U.S. Open champion was quoted as saying by the Moscow organisers.
"I have played a lot this year and my body needs to recover. My goal is to try and get the number one ranking back," said the American, who will relinquish the number one spot to Serbia's Jelena Jankovic when the new rankings are released on Monday.
Williams reached the final last year in Moscow, losing to Elena Dementieva.
Australian Open finalist Jo-Wilfried Tsonga also withdrew because of an abdominal injury.
The women's field is the strongest in the 19-year history of the $2.3 million tournament, which starts in Moscow on Monday, with eight of the world's top 10 players taking part.
Only Williams and world number six Maria Sharapova, who is nursing shoulder injury, are absent. (Reporting by Gennady Fyodorov; editing by Pritha Sarkar)