NEW YORK — Forget about forehands and backhands. Melanie Oudin's biggest weapon is her heart.
The 17-year-old sparkplug from Georgia proved it again Monday at the U.S. Open, extending her remarkable run to the quarterfinals with another come-from-behind victory, 1-6, 7-6 (2), 6-3 over 13th-seeded Nadia Petrova.
Oudin staved off two points that would have put her behind 5-3 in the second set, then rolled through the third, hitting corners with those underrated groundstrokes and taking advantage of 22 unforced errors by her more seasoned opponent.
The 70th-ranked player, who won the RBC Bank Challenger in Raleigh in May, already had comeback wins over No. 4 Elena Dementieva and No. 29 Maria Sharapova at Flushing Meadows, along with one over former No. 1 Jelena Jankovic this summer at Wimbledon. Now, she has knocked off No. 13.
She has become the youngest American to move into the quarterfinals at America's Grand Slam since Serena Williams in 1999.
The first major quarterfinal of her nascent career will come against No. 9 Caroline Wozniacki of Denmark, who added to the stream of upsets in the women's tournament by knocking off sixth-seeded and two-time major champion Svetlana Kuznetsova 2-6, 7-6 (5), 7-6 (3).
"I think this is going to do a lot," Oudin said. "I think it's good for American tennis."
After hitting a forehand to the corner for her 19th and final winner on match point, Oudin threw her racket into the air. This time, however, she didn't cry any tears of disbelief. Instead, it was twin sister Katherine sobbing in the stands.
"It's kind of hard to explain how I've done it," Melanie said. "Today, there were no tears because I believed I can do it. Now I know I do belong here. This is what I want to do. I can compete with these girls no matter who I'm playing. I have a chance against anyone."
On the men's side, John Isner of Greensboro lost to No. 10 Fernando Verdasco, 4-6, 6-4, 6-4, 6-4, in Armstrong Stadium, assuring the men's quarterfinals will be without an American for the first time in history. Isner, 6 feet 9, had eliminated fifth-seeded Andy Roddick in the third round.
Next door in Ashe Stadium, No. 1 Roger Federer extended his U.S. Open winning streak to 38 with a straight-set victory over No. 14 Tommy Robredo. Next up in the quarterfinals for Federer is a match against No. 12 Robin Soderling, whom Federer beat in the final of this year's French Open to complete his career Grand Slam.
Soderling advanced when No. 8 Nikolay Davydenko retired with a leg injury at the start of the fourth set.