American Melanie Oudin continued her remarkable run at the US Open with a 1-6 7-6 (7-2) 6-3 win over Nadia Petrova to reach the quarter-finals.

It seemed that luck had run out for the 17-year-old as she was overpowered in the first set by the Russian 13th seed.

But back came Oudin to win the next on a tie-break and she then broke serve twice in a tense final set to record another famous victory.

Oudin will play Danish ninth seed Caroline Wozniacki in the last eight.

Wozniacki, 19, beat sixth seed and 2004 champion Svetlana Kuznetsova 2-6 7-6 (7-5) 7-6 (7-3) in the night session.

"I didn't think I started off too well and Nadia served unbelievable," said Oudin, ranked 70 in the world.

"But I stayed in there with her in the second set and she gave me a few free points and I got my confidence and I believed I could do it, and I did it."

The teenager from Marietta in Georgia, who reached the last 16 at Wimbledon, beat Maria Sharapova and fourth seed Elena Dementieva in previous rounds.

Oudin has a 17-4 record in the three-set matches she has played and this was her fourth successive victory over a Russian opponent.

"It's kind of hard to explain how I've done it," said Oudin. "There are no tears because I believed I could do it and it's like now I know that I do belong here.

"This is what I want to do and I can compete with these girls no matter who I'm playing. I have a chance against anyone."

Wozniacki fought back from a set down in the first of the night matches on Arthur Ashe Stadium as French Open champion Kuznetsova struggled with unforced errors.

"She was putting balls back but I lost to myself because I did so many unforced errors," said Kuznetsova. "These unforced errors, you cannot win against nobody. It's no chance."

Looking ahead to facing Oudin, Wozniacki said: "I think we've both played some really good tennis. I enjoy playing on the big stadiums with such a huge crowd even though I know they will always be behind Melanie next match."

Earlier, Ukraine's Kateryna Bondarenko trounced Argentina's Gisela Dulko 6-0 6-0 to book a spot in the US Open last eight.

Dulko was a shadow of the player that beat Maria Sharapova at Wimbledon this year, with the double bagel scoreline achieved in only 47 minutes.

"I got some messages to get revenge," Bondarenko said referring to sister Alona's defeat by Dulko in round two.

Bondarenko will now play 19-year-old Belgian Yanina Wickmayer, who recorded a 4-6 6-4 7-5 win over Czech player Petra Kvitova - conqueror of top seed Dinara Safina in the third round.