Petrova defeated her next opponent, Safina, two weeks ago at the Sony Ericsson Open in Miami and she has no doubt she can repeat the result.

BBC: SPORT | Tennis | Petrova and Williams both advance

Wednesday's unexpected withdrawal follows that of second-ranked Azarenka, which ensured that Williams will hang on to top spot until the Sony Ericsson Open, which starts in Miami on March 18.

CNN: STORY HIGHLIGHTS

In Miami, where Mr. Murray is scheduled to play his first match of the Sony Ericsson Open Friday morning, the world No. 4 is still very much a man chasing starlight: Despite being stronger, faster, smarter, more versatile and more dedicated than ever, he seems to get no closer to the object of his desire.

WSJ: Andy Murray Tries to Crack Tennis's Inner Circle