WIMBLEDON, England -- Top-ranked Dinara Safina of Russia became the first player to win a match under Wimbledon's new roof, rallying to beat Amelie Mauresmo of France 4-6, 6-3, 6-4 for a spot in the quarterfinals.
The match was interrupted with Safina leading 4-1 in the second set for the first rain delay of the tournament. The roof was closed before play resumed about 30 minutes later.
When the roof closed, many spectators responded with a standing ovation. Safina liked the new environment, too.
"It was great," she said. "Very nice. You can't compare it with anything. It's a really nice atmosphere, especially with the crowd, because it's getting like louder so it's even nicer to play. I mean, I won, so everything was perfect."
Venus Williams advanced to the quarterfinals when opponent Ana Ivanovic retired one game into the second set. Second-seeded Serena Williams also advanced with a 6-3, 6-1 win over Daniela Hantuchova, losing just two points on her first serve and breaking Hantuchova five times to complete the win in 56 minutes.
Venus led 6-1, 0-1 when Ivanovic called it quits.
Ivanovic took a 10-minute break during the first game of the second set to have her left thigh taped by a trainer. She returned for two more points, but after hitting a service winner to take the game, she began crying as she walked to her chair and told the umpire she was retiring.
Ivanovic said she hurt her thigh hitting an ace to erase a break point in the opening game of the second set.
"I didn't feel anything up until that point," she said. "When I landed, I just felt a sharp pain on my inner thigh, and I couldn't step on my leg ever since."
Ivanovic said she didn't yet know the extent of the injury.
Venus, seeking her sixth Wimbledon title, took a 5-0 lead before Ivanovic won a game 27 minutes into the match. Former No. 1 Ivanovic hasn't reached a Grand Slam quarterfinal since winning the 2008 French Open.
"I don't even know the last time that I had these circumstances," Venus said. "I don't think ever in a Slam. I think she was in a lot of pain. You know me -- I'm one of those players, I just only pay attention to what's going on my side of the net. But today I felt really sad for her actually. She was really upset.
"This is Wimbledon. It's the last place you want to have an injury that you can't overcome. So I'm wishing her a lot of luck in her recovery," she said.
Serena is looking for her third Wimbledon title after winning here in 2002-03. She lost last year's final to her sister.
American 17-year-old Melanie Oudin was eliminated.
Oudin, a qualifier from Marietta, Ga., lost to No. 11-seeded Agnieszka Radwanska 6-4, 7-5.
Missed chances hurt Oudin. She flubbed an easy volley to lose the first set, and she was up a break in the second set before her surprising Wimbledon came to an end.
"I gave everything I had, and she played a really good match," Oudin said. "She played very smart. She made me run as much as she possibly could."
Oudin pulled the biggest upset in the first week of the tournament by beating former No. 1 Jelena Jankovic. Oudin was the youngest American to reach the women's fourth round at Wimbledon since Jennifer Capriati was a quarterfinalist in 1993.
Azarenka battled her way into the quarterfinals with a hard-fought 7-6 (5), 2-6, 6-3 victory over Russia's Nadia Petrova.
The eighth seed, the first woman from Belarus to reach the last eight at Wimbledon since Natasha Zvereva in 1998, will have to raise her game to stand a chance against Serena Williams in the last eight.
An abysmal first set was awash with unforced errors, both players losing serve three times apiece before Azarenka, yowling with effort on every point, squeaked home 7-5 in a tight tiebreak.
Petrova, treated at the end of the set with ice packs to counteract the heat, came back with guns blazing to even the match but could not maintain the pressure in the decider, and Azarenka wrapped it up after 2 hours, 25 minutes.
Dementieva beat fellow Russian Elena Vesnina 6-1, 6-3.
Dementieva faced little resistance in the first set and never faced a break point in the match. She sealed the win by breaking for the second time in the second set, converting her second match point.
Dementieva is playing her 11th consecutive Wimbledon tournament and reached the semifinals last year.
Information from The Associated Press and Reuters was used in this report.