Maria Sharapova [Images] fought her way out of trouble to beat sixth seed Nadia Petrova 7-6, 6-4 in an all-Russian quarter-final at the Australian Open on Tuesday.

Sharapova had to dig deep and break her opponent twice to force the opening set to a tie-breaker, then saved two set points before winning a first set that featured six service breaks.

The former Wimbledon champion struggled in an error-strewn second set, but after fending off three break points at 5-4, she closed out the match in two hours.

"It was definitely not easy. We were breaking each other's serves left and right out there. It was a miracle when someone held serve," Sharapova told a news conference.

"I just tried to hang in there. It's really tough being down two set points. But I gutted it out in the first point, then had an easy second point."

Sharapova, a semi-finalist in Melbourne last year, plays either top seed Lindsay Davenport [Images] or eighth seed Justine Henin-Hardenne in Thursday's semi-finals. They were due to play each other Tuesday night.

Petrova said she only has herself to blame for losing.

"I just feel like I simply gave it away," Petrova said.

"I had all the chances in the first set ... but I must say she fought hard for it.

"There's nothing I can do about it now. I can just go through my mistakes and get my head cleared from all this and just move forward."

DISTRACTION

Both Russians struggled with their serves and groundstrokes on a windy day at Melbourne Park.

Petrova grabbed the first break but failed to consolidate and missed her chance to take the first set when she failed to serve it out in the 10th and 12th games.

Sharapova, urged on by her father Yuri from the stands, opened up a 2-0 lead in the second but also failed to consolidate.

Petrova broke back but dropped her serve again to give Sharapova the gap she needed to clinch the match.

Australia's former world number one John Newcombe had set the foundations for a controversial match by claiming Sharapova's loud grunts during games were distracting her opponents.

"If I was playing against someone who was doing it all the time, I would ask for the referee and say the player has to stop," he was quoted as saying in the Herald Sun newspaper.

But Petrova played down the issue, insisting she had no cause for complaint.

"I can't say it's a distraction because, first of all, when she start grunting, it means she's getting tight," Petrova said.

"It doesn't bother me. It doesn't bother me at all. If it would, I would definitely go and tell him [the umpire]."

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