Roger Federer will take on No. 13 Robin Soderling in a rematch of the French Open final on Monday at Wimbledon, one of several intriguing matches on Day 7 of the tournament.

The Williams sisters highlight play on the women's side. Five-time women's champion Venus Williams plays No. 13 Ana Ivanovic, while younger sister Serena goes up against Daniela Hantuchova.

There was no play at Wimbledon on the first Sunday of the fortnight, as the weather co-operated even with a new retractable roof at Centre Court able to be used if needed.

There was a grizzled look to the men's field, at least by tennis standards, after one week at Wimbledon.

Those reaching the gentlemen's round of 16 included six players age 27 or older, among them Tommy Haas, 31, and Radek Stepanek and Ivo Karlovic, both 30. The message: When it comes to the brief lawn tennis season, experience pays.

''Grass definitely takes some getting used to,'' said Andy Roddick, 26, who reached Week 2 for the fifth time in nine Wimbledons. ''If you've played on it for years, and years, and years and years, I think the adjustment period will be probably a little bit quicker.''

Women's side strong on youth

Among those reaching the women's fourth round were 17-year-old American Melanie Oudin in her Wimbledon debut, and 19-year-old German Sabine Lisicki, who won a match on grass for the first time Tuesday.

''I just can't believe I'm in the fourth round,'' Lisicki said.

Two other teenagers made it — 19-year-old Victoria Azarenka of Belarus and 18-year-old Caroline Wozniacki of Denmark.

The youngest remaining player was also the most surprising. Oudin arrived in London with a ranking of 124 and an 0-2 record in Grand Slam matches, but beat No. 29 seed Sybille Bammer in the first round and No. 6 Jelena Jankovic in the third.

Oudin declined to grade her level of excitement.

''I'm going to answer that after the tournament's over,'' she said, ''because it could get higher as the tournament goes on.''

Oudin's win over former No. 1 Jankovic was the most surprising result of the first week. Another upset: The new retractable roof on Centre Court was unused during the first half of the fortnight, causing snickers in the locker-room.

''The common joke has been that they haven't had to use it yet,'' Roddick said. ''All this money, and the weather has been nice.''

There's still a long way to go, with a parade of talent Monday, when all 16 fourth-round matches have been scheduled.

''It's a good ticket, I guess, if you're a tennis fan,'' Roddick said. ''Even if you don't get on centre, your grounds pass will do just fine.''

The showcase matchup was five-time champion Federer against Soderling. Federer completed a career Grand Slam by beating Soderling in the French Open final three weeks ago.

On the women's side, Russians made up a quarter of the final 16. On the men's side, 13 countries remained represented, reflecting the global reach of the sport.

One unlikely survivor of the first week was Spain's Juan Carlos Ferrero, who needed a wild-card invitation to get into the tournament. At 29, the former No. 1 has slipped to 70th in the rankings after a series of injuries.

Another surprise was No. 46-ranked Dudi Sela, the first Israeli man to reach the fourth round at Wimbledon since his idol, Amos Mansdorf, did it 20 years ago.

''It's very special for me,'' Sela said. ''Back home I think, for a long time, people were waiting for someone, for a man, to be in the fourth round.''

'With my serve, I feel OK'

Sela became the fourth Israeli man to reach the round of 16 in a Grand Slam tournament. He did it on grass despite growing up playing almost exclusively on hard courts and, at five-foot-nine, being smaller than a lot of top pros.

''The ball is bouncing lower on the grass, so maybe I'm in a better position than other players,'' Sela said.

At the other extreme is the six-foot-10 Karlovic, long considered dangerous at Wimbledon because of his serve. He had 102 aces in the first three rounds.

''With my serve, I feel OK,'' he said. Smiling, he added, ''If I can win with only one shot, I'm a genius.''

Karlovic's opponent Monday was No. 7-seeded Fernando Verdasco. Sela was to play No. 4 Novak Djokovic, and Roddick was to face No. 20 Tomas Berdych.

On the women's side, Oudin's opponent was No. 11 Agnieszka Radwanska. Serena Williams was to face Daniela Hantuchova.