New York:Roger Federer overcame a sloppy first set and tumble to the court to beat two-time Grand Slam champion Lleyton Hewitt 4-6, 6-3, 7-5, 6-4 on Saturday and reach the fourth round of the US Open.
Federer has won 14 consecutive matches against Hewitt, and 37 in a row at Flushing Meadows.
"I knew that being down a set against Lleyton is always going to be a difficult situation for me to be in: Make one more mistake and I'm in the fifth set, maybe, or I go down completely," said Federer, trying to become the first man since the 1920s to win the American Grand Slam tournament six consecutive years.
"So I was relieved coming through."
Federer's opponent in the last 16 will be Tommy Robredo, with the Spaniard beating American James Blake in straight sets.
The tournament provided its first major upset in the men's draw as American John Isner edged fifth-seeded compatriot Andy Roddick 7-6 (3), 6-3, 3-6, 5-7, 7-6 (5).
"It's hands down the biggest win of my career. Nothing even compares," Isner said. "To do it at the stage I did it on is pretty spectacular. But I know I can really do some damage here. So I'm not satisfied just yet."
Roddick was the first of the top 16 men to lose this week. He won the 2003 Open and came within a whisker of winning Wimbledon in July, but he now must resume his pursuit of a second career major title next year.
Instead, it's the 2.03-meter (6-foot-9) Isner moves on, thanks to some outstanding serving and success at the net: He won 42 of 67 points when he pushed forward.
Isner's fourth-round opponent will be Spaniard Fernando Verdasco, who edged Tommy Haas in a five-set thriller.
Serbian No. 4 seed Novak Djokovic also had a struggle with a lowly ranked American opponent before prevailing 6-7 (2), 6-3, 7-6 (2), 6-3 over No.276-ranked Jesse Witten. Djokovic's next assignment is Slovakia's Radek Stepanek.
Nikolay Davydenko had a more comfortable passage to the fourth round, with the eighth-seeded Russian defeating Switzerland's Marco Chiudinelli 6-4, 7-5, 7-5. He set up a clash with French Open finalist Robin Soderling, who beat Sam Querrey in four sets.
In the women's draw, top-seeded Dinara Safina was ousted, beaten 6-4, 2-6, 7-6 (5) by 72nd-ranked Petra Kvitova of the Czech Republic. After escaping the first two rounds with poorly played three-set victories, Safina wasted three match points Saturday and finished with nine double-faults and 39 total unforced errors.
Her departure means the Williams sisters are the only members of the top five women left in the field.
Kvitova will face Yanina Wickmayer in round four, with the top quarter of the draw shorn of all its seeds.
Former champion Svetlana Kuznetsova accelerated to a 7-5, 6-1 victory over Israel's Shahar Peer, putting the sixth-seeded Russian in the fourth round.
She will next meet Denmark's Caroline Wozniacki, who progressed with a 6-3, 6-2 defeat of Romania's Sorana Cirstea.
The major talking point for American fans was the continuation of 17-year-old Melanie Oudin's giant-killing run, as she fought back to beat former world's No.1 Maria Sharapova 3-6, 6-4, 7-5.
Sharapova double-faulted 21 times, the most by a woman in any 2009 tour match. But Oudin's solid groundstrokes and tremendous court coverage played significant roles, too.
"I try to pretend that it's not Arthur Ashe Stadium, playing Maria Sharapova," Oudin said. "I try to just pretend it's any other match _ even just practicing. Sometimes I tell myself I'm just practicing at my academy at home, and I'm just playing one of my friends."
Oudin is the youngest American woman in the U.S. Open's final 16 since Serena Williams a decade ago.
"Got to hand it to her," Sharapova said. "She really stuck to her game plan. She played solid. She made me hit a lot of balls."
Sharapova compiled 63 unforced errors, 19 more than Oudin. All those double-faults, several at key moments, helped Oudin compile an astounding 26 break points _ and she converted eight.
Oudin next faces a fourth consecutive Russian ranked higher than she is: No. 13 Nadia Petrova.