Petrova beat the Swiss player, once the dominant force in women's tennis, 6-2 6-2 with an impressive display of powerful serving.

Hingis, who missed over three months of the season after ankle surgery in May, struggled from the start and was run around the court on her 22nd birthday.

"I have missed out on so much of the season that really today I was finding the game I need to play," said Hingis, the number five seed.

"(But) it is difficult to get into a rhythm playing Nadia because of her serve.

"It was a difficult match and I was unlucky to lose on my birthday."

Petrova said: "I knew it was her birthday and I congratulated her before the match, but that's tennis, that's sport."

The Russian player used her height to impressive effect in her own service games, sending thumping deliveries into the corners of the court.

Hingis' serve, meanwhile, looked feeble in comparison and she was unable to control the match.

"I think I play better than I used to two years ago, but it's not enough anymore...the girls are very strong these days," Hingis said.

"I need to go home and practise now. For me right now tennis should be the priority."

Petrova could meet compatriot and tennis pin-up girl Anna Kournikova in the second round, a prospect which she is relishing.

"I think the next match could be interesting for the public and I intend to play well," she said.