Wimbledon, England ? Justin Gimelstob keeps falling into what he calls tennis “oblivion,” losing more than he wins, dealing with injuries, then doing whatever it takes to get back on the scene, whether it’s crisscrossing the globe for minor events to raise his ranking or taking a dangerous number of painkilling injections.

A week after quitting during a qualifying match because of a bad back, then getting into the main draw when someone pulled out, Gimelstob knocked off Olympic gold medalist Nicolas Massu, 6-3, 4-6, 7-6 (5), 7-6 (0), at Wimbledon on Wednesday to set up a third-round match against 2002 champion Lleyton Hewitt.

“He plays with a lot of passion out there,” Hewitt said.

Nine U.S. men entered the tournament, and after three days, just a trio is left – with the 123rd-ranked Gimelstob the unlikeliest. Taylor Dent, seeded 24th, beat countryman Kevin Kim, 6-3, 6-4, 6-4, Wednesday to reach the third round, while No. 2 Andy Roddick faces Daniele Bracciali of Italy in a second-round match today.

No. 29 Massu was one of three seeded men who lost. No. 22 Dominik Hrbaty was beaten by 18-year-old Gael Monfils, who won three junior Slams in 2004, and No. 8 Nikolay Davydenko, a French Open semifinalist, retired with a right wrist injury.

Hewitt beat Jan Hernych, 6-2, 7-5, 3-6, 6-3; Roger Federer extended his Wimbledon winning streak to 16 matches with a straight-set victory over Ivo Minar; and two-time major winner Marat Safin got past 2003 Wimbledon runner-up Mark Philippoussis, 7-6 (4), 7-6 (4), 6-4, in a match interrupted when the Centre Court net suddenly collapsed.

“I’ve been here a long time, since 1977, and I watched on TV as a kid,” John McEnroe said. “And I’ve never seen that happen.”

No seeded women lost, with No. 1 Lindsay Davenport, No. 3 Amelie Mauresmo and No. 15 Kim Clijsters advancing in straight sets.

Three top Russians struggled, though: U.S. Open champion Svetlana Kuznetsova beat Sania Mirza, 6-4, 6-7 (4), 6-4, despite getting broken six times and committing 30 unforced errors; 2004 French Open champion Anastasia Myskina needed 13 set points to close out the opener in her victory over Aiko Nakamura; and two-time Slam finalist Elena Dementieva double-faulted 17 times but defeated Sabine Klaschka, 2-6, 6-3, 8-6.