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 quarter-finals 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, higher-ranked opponent.
Rankings, like her age, however, are only numbers.
The 70th-ranked player already had 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's knocked off No. 13.
Too young to know any better? Maybe. Regardless, she has become the youngest American to move into the quarter-finals at America's Grand Slam since Serena Williams in 1999.
"I think this is going to do a lot," Oudin said. "I think it's good for American tennis."
Not so good for Russian tennis, though.
All four of Oudin's wins have come against Russians and her next match could be against yet another. That's sixth-seeded Svetlana Kuznetsova, the 2004 Open champion and the only Grand Slam tournament winner left on Oudin's side of the bracket.
After hitting a forehand to the corner for her 19th and final winner on match point, Oudin threw her racket in 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."
Talk about heart. Oudin improved to 6-1 at Wimbledon and the U.S. Open this year when she's lost the first set. She is 17-4 overall this year in three-set matches.
"I don't actually mean to lose the first set," she insisted. "Sometimes, I just start off slowly. Maybe I'm a little nervous. Today, my timing was off a little. But I just totally forgot about it, started off the second set like it was a new match, and I started playing better."
Oudin won this match without serving a single ace, another indication she is not blowing anybody away with sheer power. Instead, it's footwork, technique, precision. Mostly, though, she is thriving in pressure situations that make so many others in the sport shrink away.
"You don't know if she's winning or losing," said her father, John. "She doesn't seem nervous out there - and I don't know where that came from."
In men's action, No. 12 Robin Soderling, a French Open finalist after beating Rafael Nadal, advanced when No. 8 Nikolay Davydenko retired with a leg injury at the start of the fourth set. No. 1 Roger Federer had an afternoon match and John Isner was trying to prevent this from becoming the first U.S. Open without an American man in the quarter-finals.
In doubles, Toronto's Daniel Nestor and Serbian partner Nenad Zimonjic escaped with a 6-2, 5-7, 6-4 win over American Robert Kendrick and Janko Tipsarevic of Serbia.
Second-seeded Nestor and Zimonjic, who have won seven doubles titles this season, will next play the No. 5-ranked duo of Max Mirnyi of Belarus and Israel's Andy Ram.
"We're playing well and we've won a lot of matches," said Nestor, 37. "I'm sure we are tough to beat but we also can't take anything for granted.
"These courts are fast and Mirnyi and Ram are good servers. It will likely come down to one or two points in the next match."