Azarenka looks to protect top ranking, Sharapova out

MONTREAL (Reuters) - Victoria Azarenka will play her first match since the London Olympics on Thursday at the Montreal Cup with only one threat to her status as the world's top female player left in the draw.

Both Maria Sharapova and Agnieszka Radwanska came to Canada with a chance at uprooting Belarusian Azarenka, who will play Austrian Tamira Paszek in her opening match, from her perch atop the world rankings.

But the sudden withdrawal of the Russian world number two earlier on Wednesday leaves only Radwanska, who will play German Mona Barthel in an early match on Thursday, as a threat.

Sharapova, the Olympic silver medalist, withdrew from the August 4-13 Montreal event citing a stomach virus that had been bothering her since the London Games.

For Radwanska to reach the top of the world rankings for the first time, she needs to win the $2 million tournament and hope Azarenka is eliminated before the quarter-finals.

Sharapova, replaced in the draw by Galina Voskoboeva, said she initially felt unwell a day before her 6-0 6-1 loss to Serena Williams in the gold medal decider last Saturday but that the illness had worsened since arriving in Canada.

"I came to Montreal hoping that I would recover but this morning I was still not very well, so I was not going to be able to practice which is, you know, not the best preparation in order to compete tomorrow," she told reporters on Wednesday.

"We want to have the best preparation we can for the U.S. Open and this is a really big tournament for us. Personally, I was here in order to play the tournament. I was ready but my body is just not ready for it, so you kind of have to make the smart decisions for your body."

Petra Kvitova and Sam Stosur, who was runner-up to Williams in this tournament last year, were both successful in their first matches at the event on Wednesday night.