WIMBLEDON, England (AP) – Needing one more game to wrap up his first week of work at Wimbledon, Roger Federer wavered, losing his serve for the first time in the tournament.

Was the problem nerves? World Cup fever? The surprising sight of London sunshine?

“Um, you know, it just happened,” Federer said. “I wonder why. Thank God, I bounced back.”

Lapses rarely last long for Federer, especially on grass. He broke serve in the next game to close out a third-round victory Friday, beating Nicolas Mahut 6-3, 7-6 (2), 6-4.

Three-time defending champion Federer extended his record grass-court winning streak to 44 matches, digging in from the baseline against a relentless net-rusher. Mahut played serve-and-volley at almost every opportunity, but with limited success – he lost 30 of 72 points using the strategy.

“He’s taking so many chances, it doesn’t really allow you to play your game,” Federer said. “These opponents are always very tricky. I enjoy the challenge, though.”

Federer’s opponent Monday will be familiar to him: No. 13-seeded Tomas Berdych, who advanced by outlasting No. 19 Tommy Haas 2-6, 7-5, 7-6 (7), 4-6, 8-6. Berdych lost to Federer last week on grass in Halle, Germany, and also four weeks ago on clay at the French Open.

But Berdych upset Federer on a hard court at the Athens Olympics in 2004.

“That is for me a very tricky match,” Federer said. “It’s quite a tough draw I have this year.”

Richard Gasquet and Tim Henman, both comfortable on grass, faced Federer in the first two rounds and won a total of 13 games. Mahut offered a little more resistance.

Ranked 77th, the Frenchman is – like Federer – a former Wimbledon juniors champion. Mahut began the tournament 0-9 in Grand Slam events, but he had never played in the main draw at Wimbledon, and his big serve and aggressive tactics make him dangerous on the speedy surface.

“We had many, many points that were over in no time,” Federer said. “You don’t really get a momentum going. I knew I had to wait for my chance. I was actually pretty relaxed all the way through. I think that was pretty important – not getting frustrated against a player like this.”

Statistics provided proof that Federer kept his cool. He had 50 winners, including 15 on passing shots, and only 13 unforced errors.

Making the afternoon even better for the Swiss star: Two potential obstacles in his half of the draw were upset. No. 4-seeded David Nalbandian, who has a 6-6 record against Federer, lost to Fernando Verdasco 7-6 (9), 7-6 (9), 6-2. No. 8 James Blake was eliminated by Max Mirnyi 6-4, 3-6, 4-6, 6-1, 6-0.

The last man other than Federer to win Wimbledon, 2002 champion Lleyton Hewitt, beat Lee Hyung-taik in the completion of a suspended second-round match, 6-7 (4), 6-2, 7-6 (6), 6-7 (5), 6-4. Hewitt wouldn’t face Federer until the final.

“Right at the moment I don’t have to worry about Roger,” Hewitt said. “If it comes to that, it won’t be an easy matchup, that’s for sure. But I’ve got a lot of hurdles before I get to him.”

When not at the All England Club, Federer has been scouting Hewitt and other possible future opponents on BBC telecasts.

“I enjoy watching other matches, ladies’ or men’s – obviously the men’s a little more,” he said. “I’m watching a fair bit of it, but not crazy, because I also have another life. I also want to do something else than just focus on tennis all the time – going to the city, go somewhere, do something else.”

With his latest Wimbledon win, Federer earned a chance to play tourist this weekend.

AP-ES-06-30-06 1734EDT