MELBOURNE -- Top-ranked Lindsay Davenport set up a quarterfinal match with Justine Henin-Hardenne in the Australian Open, overcoming left ankle pain and a second-set lapse to beat Svetlana Kuznetsova, 6-2, 6-4, today.
The eighth-seeded Henin-Hardenne beat Virginia Ruano Pascual, 6-0, 6-3.
Davenport finished off Kuznetsova in 59 minutes, winning on her second match point.
The 2000 Australian Open winner swept through the first set in 18 minutes, losing only 2 points on her serve and breaking Kuznetsova twice.
In the second set, Davenport raced to a 3-0 lead before Kuznetsova rallied, reeling off four consecutive games.
During that time, a clearly frustrated Davenport sought treatment for her left ankle, asking the trainer to remove and replace heavy strapping. She twisted the ankle in her last match and her movement was hampered in the second set.
''I sprained it a little bit the other day," said Davenport, who finished with 15 winners and only nine unforced errors. ''It was just a little bit swollen. I kind of jammed it on one shot. Hopefully, it will have a little time to get better."
Davenport, a finalist last year in the Australian and US Opens, said she is playing better now than she was in 2000, when she captured her last Grand Slam singles title at Melbourne Park.
''I feel like I'm playing some of my best tennis," Davenport said. ''It's unfortunate that all the other girls are playing so much better. This is the highest level we've ever competed at."
Henin-Hardenne, the reigning French Open champion and 2004 Australian winner, lost 5 points on her serve in the first set against Ruano Pascual.
Ruano Pascual had never taken a set off Henin-Hardenne in their three previous matchups, and there was nothing different, with the Belgian dictating play.
Although she finished with 27 unforced errors -- 20 in the second set -- Henin-Hardenne also hit 28 winners to just one from Ruano Pascual.
Henin-Hardenne broke early in the second set, led, 3-1, fended off two break points at 3-2, and wrapped it up by breaking the Spaniard in the ninth game with a forehand pass.
In the opening match under the roof at Rod Laver Arena, sixth-seeded Nadia Petrova beat fellow Russian Vesnina, 6-3, 6-1. Petrova will meet the winner of a late match between 2004 Wimbledon champion Maria Sharapova and Daniela Hantuchova.
Hantuchova beat 2005 champion Serena Williams in the third round.
Heat forced organizers to invoke the extreme heat policy for a third consecutive day, suspending play on outside courts when the temperature exceeded 97 before noon. All fourth-round singles matches were scheduled under closed roofs at the two arenas.
The forecast was for the temperature to rise to 106.
Yesterday, when the temperature reached 104 and proved the most formidable opponent, Roger Federer advanced with a 6-3, 6-4, 6-3 victory over 30th-seeded Max Mirnyi of Belarus.
Federer will have some company in Martina Hingis. Coming back from three years in retirement, Hingis clearly seems to be on her game, her latest victory a 6-4, 6-1 decision over Iveta Benesova of the Czech Republic.
Federer is happy to see someone else carry the Swiss flag in the season's first major.
''Fantastic. I'm extremely happy she's back," he said. ''I really hope she can go a long way. Being a Swiss, I'm really excited."
Federer advanced to play Tommy Haas, who beat him in the 2002 Australia Open and, more recently, in an exhibition last week at Kooyong.
''I'm really looking forward to that match," said Federer, 8-0 this season.
Hingis is trying to conserve as much energy as she can. She has dropped only 10 games in three rounds.