MELBOURNE, Australia - German Rainer Schuttler defeated Daniel Nestor of Toronto 6-4, 6-2, 7-5 in men's third-round action Saturday at the Australian Open. Nestor served six aces in the two-hour five-minute match, but also committed 59 unforced errors to Schuttler's 32 in dropping out of singles play. Nestor said the lack of a good night's sleep left him listless.

I must have woken up five or eight times last night, Nestor said. I was just stressing myself out. It only happens in singles.

I should have been happy to be in the third round of a Grand Slam look at the match as a bonus. Instead, I spent all of my time worrying about it.

It is the first time the German has reached the round of 16 at a Grand Slam event.

The Canadian remains active in doubles play with partner Sandon Stolle of Australia. The two are the top seeds.

Meanwhile, Amelie Mauresmo advanced to the women's fourth round, where she'll face Venus Williams, the No. 3 seed who finished off Denisa Chladkova 6-4, 6-1.

The 13th-seeded Mauresmo, the 1999 runner-up, beat former French Open champion Iva Majoli 6-4, 6-2.

Williams faces her first seeded opponent in Mauresmo.

It's somewhat like two tournaments, Williams said. The first week is possibly more dangerous. You're playing the lower-ranked players and have to be on your guard.

For the second consecutive day the weather was sunny and hot, with the temperature expected to peak at 36 C and soaring to 51 C on the hardcourts.

Serena Williams, eager to get out of the heat, beat Tamarine Tanasugarn 6-1, 6-4 in 58 minutes and No. 1 seed Martina Hingis joined her in the round of 16 just 18 minutes later by beating wild-card entry Virginie Razzano on an adjacent court 7-5, 6-1.

Serena Williams complained more about the wind than the heat. Despite winning in 58 minutes, she was annoyed by her performance.

I'm pretty disappointed with the way I played, she said. The wind was kind of chasing the ball a little. I didn't do the things I wanted to do.

Seventh-seeded Mary Pierce wilted in the weather, losing to Paola Suarez 6-3, 6-2. No. 10 Amanda Coetzer beat Marlene Weingartner 6-2, 6-4. Unseeded Rita Grande beat Australian Evie Dominikovic 6-3, 6-4.

Two Frenchmen advanced. No. 15 Arnaud Clement beat Roger Federer 7-6 (5), 6-4, 6-4, and No. 16 Sebastien Grosjean beat Thomas Johansson 6-4, 6-1, 6-4.

Mauresmo was 0-for-5 on break-point opportunities before Majoli dumped a backhand into the net to lose the first set. Mauresmo broke again for a 2-0 lead in the second set, never lost serve and closed out the win in one hours 16 minutes. The Frenchwoman has yet to drop a set in three rounds.

Mauresmo, who was unseeded when she lost the 1999 final to Martina Hingis, has struggled with a lower back injury since last spring. She was ranked sixth a year ago but has slipped to 20th.

On Friday, Nestor and compatriot Sebastien Lareau, playing with different partners after teaming up for Olympic gold in Sydney, advanced to the third round of the men's doubles competition.

Nestor and Stolle beat Eyal Ran of Israel and Alberto Martin of Spain 6-2, 6-2.

Lareau, from Boucherville, Que., and American Alex O'Brien had a tougher time against Lucas Arnold and Gaston Etlis of Argentina. Lareau and O'Brien, the fifth seeds, prevailed 3-6, 6-1, 6-4.

Midway through the final set in his third-round match Friday, a weary Pete Sampras made for the shade and took a seat in a lineswoman's chair.

Felt like I was playing on hot coals, he said.

Sampras engaged in his third three-hour match this week, it was no wonder he wanted to sit. That he was able to get up again was perhaps surprising.

After his brief respite, Sampras closed out a comeback victory, beating Juan Ignacio Chela 6-4, 4-6, 4-6, 7-5, 6-2 in three hours eight minutes.

That made nine hours 26 minutes of tennis for the third-seeded Sampras. With a match against Todd Martin next, followed by a likely showdown against Andre Agassi in the quarter-finals, it was uncertain how much stamina Sampras had left.

I've seen him win Slams injured, so I don't buy any of it, Agassi said. If he's tired or not, you've got to beat him. If he's injured or not, you've got to beat him.

One of the things he has proven over the past decade is that it's not easy to do.

The sixth-seeded Agassi, who followed Sampras on centre court, caught a break when his opponent, David Prinosil, retired because of heat exhaustion after about an hour. Agassi overcame a 6-2 deficit in a first-set tiebreaker and led 7-6 (11), 5-0 when Prinosil quit.

It would have been nice to finish, said Agassi, the defending champion. But he's OK and I'm on to the next round, so that's all good.