One surprising run ended in the fourth round. Melanie Oudin, a 17-year-old qualifier from Marietta, Ga., who never won a Grand Slam match before last week, lost to No. 11 Agnieszka Radwanska of Poland 6-4, 7-5.

"It's always difficult to play someone who you don't know," said Radwanska, who did not appear to have any difficulty Monday, but might find the road rougher Tuesday.

That's when she will play in the quarterfinals against Venus Williams, who has won 18 consecutive matches at Wimbledon and is trying to become the first woman since Steffi Graf in 1991-93 to win the tournament three years in a row.

Tuesday's other matches are No. 2 Serena Williams against No. 8 Victoria Azarenka of Belarus, Dementieva against unseeded Francesca Schiavone of Italy, and Safina against unseeded Sabine Lisicki of Germany.

The men get a day off before their quarterfinals Wednesday, when the matchups will be No. 2 Federer vs. No. 22 Ivo Karlovic of Croatia, Murray vs. 2003 French Open champion Juan Carlos Ferrero, Djokovic vs. No. 24 Tommy Haas, and Roddick vs. 2002 Wimbledon champion Lleyton Hewitt, who lost the first two sets but came back to beat No. 23 Radek Stepanek 4-6, 2-6, 6-1, 6-2, 6-2.

"Lleyton and I have built up a very healthy respect for one another throughout the years," said Roddick, who smacked 24 aces, never faced a break point and eliminated No. 20 Tomas Berdych 7-6 (4), 6-4, 6-3. "We're a couple of the old guys now."

Well, Roddick is 26, and Hewitt is 28. Neither has anything on Haas, who at 31 was the oldest man to reach the fourth round and now meets the youngest, Djokovic, who was born a week after Murray.

Federer improved to 11-0 against Robin Soderling by beating him in straight sets in a rematch of the French Open final three weeks ago. Now Federer has to deal with Karlovic, at 6-foot-10 the tallest player in tour history, who pounded 35 aces and served 10 games at love while defeating No. 7 Fernando Verdasco 7-6 (5), 6-7 (4), 6-3, 7-6 (9). Karlovic leads Wimbledon with 137 aces and has gone 128 service games over his past two tournaments without being broken."I mean maybe it's not the most fun match to go through," Federer said. "But I like to beat this guy because he makes it hard on us."

Federer and Wawrinka teamed to win the doubles gold medal at last year's Beijing Olympics. Otherwise, Wawrinka never has come close to approaching his friend's success. Bidding to reach his first major quarterfinal, though, Wawrinka gave Murray plenty of trouble.