By Steve Ginsburg

NEW YORK - America's newest heroine, Melanie Oudin, continued her dream-like run at the U.S. Open with another shocking upset on Monday while steely top seed Roger Federer forged closer to his 16th grand slam crown.

"Mentally I'm staying in there with them the whole time, and I'm not giving up at all," the 17-year-old Oudin said after reaching her first major quarter-final with a 1-6 7-6 6-3 victory over Russian Nadia Petrova.

"So if they're going to beat me, they're going to beat me, because I'm not going to go anywhere."

After belting a forehand winner to close out the match, Oudin dropped her racket, raised her arms, and looked at the sky while nearly 24,000 at Arthur Ashe Stadium roared.

On an unseasonably cool day at Flushing Meadows, the Russians concluded their worst grand slam performance in nearly a decade, while the U.S. men had their worst showing in New York since tennis turned professional in 1968.

Federer, however, was his usual brilliant self, blitzing 14th-seeded Spaniard Tommy Robredo, who was sent off bewildered after being on the receiving end of a 7-5 6-2 6-2 wallop.

"He was playing so good," Robredo said of the five-times Open winner. "When he plays like this, it's tough."

Fourth seed Novak Djokovic had an easy time bouncing 15th seed Czech Radek Stepanek 6-1 6-3 6-3 and then delighted the crowd at sold-out Ashe Stadium by impersonating John McEnroe's on-court quirks and fiery temper.

He then called McEnroe out of the broadcast booth to good naturedly play a few points.

"It actually was quite funny and the crowd loved it," said the Serb. "That was the most important thing. And Johnny, of course, made a small favor coming down.

"It wasn't easy playing in jeans and suit and collared shirt, but it was a lot of fun."

Denmark's Caroline Wozniacki managed the day's biggest upset when she toppled former champion and number six seed Svetlana Kuznetsova 2-6 7-6 7-6 to reach her first grand slam quarter-final.

The ninth seed will face Oudin in the quarters and the 19-year-old has no illusions about who will receive the crowd's backing.

"It's going to be tough, especially also with the whole crowd supporting her," Wozniacki said. "But I'm just going to go out there and enjoy."

Oudin has beaten four Russians so far, helping send the tennis power home early.

Having started with 15 women and eight men in the singles draws, all were beaten by day eight of the championships -- making it the first time since Wimbledon 2000 that no Russian reached the last eight of a grand slam singles event.

American John Isner's 4-6 6-4 6-4 6-4 loss to 10th seed Fernando Verdasco of Spain marked the first time since 1968 that no American male advanced to the Open quarter-finals.

"I didn't really care," the 24-year-old said Isner of his role carrying the U.S. hopes. "I didn't really think too much of it. I wanted to keep it going."

The story of the Open so far is the diminutive Oudin, whose never-say-die style of play and bubbly demeanor has made her the darling of Flushing Meadows.

STANDING OVATION

"It's really a great feeling," the 70th-ranked Oudin said of her support. "Everyone stood up when I had my first match point. Just when I won the second set, a standing ovation. It's crazy how many people are cheering for me and supporting me."

Oudin opened her dizzying run by defeating Anastasia Pavlyuchenkova, then shocked fourth seed Elena Dementieva and former champion Maria Sharapova.

She insists there are no secrets on how to beat a Russian.

"I don't think they had weaknesses," she said. "Every single match has been so competitive and so close, and I've been able to pull it out in the end."

Oudin scampers around the court like her idol, Belgium's former world number one Justine Henin. She chased down everything Petrova threw at her.

"When you do it for the first time you feel so excited and everything is so new and you have absolutely nothing to lose and you go and you do it," Petrova said of Oudin.

"She's on a roll, you know. She goes, enjoys it, crowd is behind her. She's having a blast out there."