Struggle for Sharapova in Hong Kong

Maria Sharapova blamed lack of competitive play after a tough 7-5, 6-3 win over world No. 166 Yan Zi of China in the quarterfinals of the Champions Challenge in Hong Kong, a warmup for the Australian Open.

The world No. 2 and two-time grand slam winner from Russia struggled to beat doubles specialist Yan, who appeared unfazed by the ranking gap and matched Sharapova stroke for stroke.

Up 5-2 in the first set, Sharapova lost serve twice to let Yan, doubles champion at Wimbledon and the Australian Open last year, even at 5-5.

She broke Yan's serve in the next game, but had a tough time serving for the set, saving three break points before winning.

The Russian -- the reigning U.S. Open champion and Wimbledon champion in 2004 -- dominated in the second set, going up 5-1 after breaking Yan twice, but then lost serve before closing out the match 6-3.

Sharapova shrugged off the tough challenge, saying at a news conference after the match that she needed time to get used to competitive conditions after training during the offseason.

"You're never going to play your best tennis in your first match," she said.

In the semifinals Sharapova will play either Czech Nicole Vaidisova or Russian Elena Dementieva.