Dubai, UAE  - World number one Serena Williams withdrew with a right knee injury before a Saturday Paris semi-final but said she hopes to be fit for next week's appearance in Dubai.

The Australian Open champion was to have faced Russian Elena Dementieva at the GDF tournament in Paris. But Williams said she felt something in her knee and withdrew as a precaution.

"I didn't feel well during the warm-up this morning, my knee hurt," said the American. "I'm extremely disappointed."

Williams said the first noticed the problem during her Friday quarter-final win over Emilie Loit.

But Williams added that with a bye at the Barclays Championships in the Gulf which begin on Monday, she should have time to recover.

"I'm optimistic, I have a day or two to treat it," she said. Williams is due to face the winner from Italian Sara Errani and Chan Yung-Jan in the second round in the Gulf.

The 2005 semi-finalist is to make here second appearance at the tournament, which features the complete Top 10 lineup. dpa