The top women's players, meanwhile, kept rolling along as No. 1 Jennifer Capriati, the Williams sisters -- Venus and Serena -- and three-time champion Monica Seles advanced to the quarterfinals.
Guillermo Canas of Argentina, Albert Costa of Spain and Andrei Pavel of Romania provided a memorable day at Roland Garros Stadium. Canas beat Hewitt, 6-7 (1-7), 7-6 (15-13), 6-4, 6-3 to reach his first Grand Slam quarterfinal.
The 15th-seeded Canas will meet No. 20 Costa, who dismissed the seventh-seeded Kuerten, 6-4, 7-5, 6-4. Pavel, who is ranked 22nd, defeated Haas, 6-1, 7-6 (11-9), 6-4.
Hewitt rallied from two sets down to beat Canas in the fourth round here last year, but the Australian struggled Sunday after losing a 91-minute second set in a 15-13 tiebreaker.
Canas finally ended the tiebreaker on his 10th set point with a crosscourt forehand winner.
"A lot of tennis matches depend on one or two points out there. He was able to get it today and I wasn't," Hewitt said.
Hewitt appeared to recover in the fourth set, winning the first three games, but Canas won the next six games to close out the match in stunning fashion.
"The end of the third set and the start of the fourth, I actually picked up my level again and was feeling pretty strong out there," Hewitt said. "And then you start hitting the wall again."
The reigning U.S. Open champion, Hewitt has won two titles this year despite coming down with chicken pox in January.
Canas came into this tournament on a hot streak, having helped Argentina to the World Team Cup crown two weeks ago, and ousted 1998 champion Carlos Moya in the the third round.
Kuerten was seeking to become the first men's player to win three straight crowns at Roland Garros since Bjorn Borg won four in a row from 1978-81 and the first since Borg to capture this event four times in a career. But the three-time champion knew that was probably unrealistic after undergoing hip surgery in February and returning to action in late April.
On Sunday, the Brazilian was unable to win a set from Costa.
"Since I'm not in top tennis shape, one of my goals here was to just get to the second week, but I knew it would be tough," Kuerten said. "I'll probably take a month to take it easy and then start again with rehabilitation."
All 11 of Costa's career tournament victories have come on clay, but he has not hoisted a trophy since 1999 in Kitzbuhel.
Pavel had lost in the first round in his past three visits to Roland Garros, but advanced to his first quarterfinals at a Grand Slam. Ten years ago, he won the junior crown here. Only two former junior champions have advanced to the final since 1988 -- 1983 boys' champion Stefan Edberg in 1989 and 1991 junior winner Andrei Medvedev in 1999.
"The performance wasn't quite as good as I wanted it to be," Haas said. "I certainly tried to hang in there and was a bit unlucky in the second set. Maybe if I used one of those set points, it could have been a different match. But if you don't win the big points, then you don't usually win big matches."
No. 18 Alex Corretja of Spain eased by Argentina's Mariano Zabaleta, 6-3, 6-2, 7-5, to advance to the French Open quarterfinals for the fifth straight year. Corretja lost the championship match to Kuerten last year and was runner-up in 1998.
"I have been to the final twice in the past five years and I want that to happen again," Corretja said. "Every time I come here I enjoy myself a lot. This is not the same feeling in the other Grand Slams. The more I win the greater my confidence becomes."
Capriati, the Australian Open winner, beat No. 20 Patty Schnyder, 6-4, 6-4 on Sunday, avenging a loss to the Swiss player last month in the semifinals at Charleston.
Capriati will meet seventh-seeded Jelena Dokic, who defeated Slovakian Katarina Srebotnik, 7-6 (7-3), 6-2, to advance to her first quarterfinal at the French Open. The 19-year-old Yugoslavian's best effort at a Grand Slam was a semifinal appearance at Wimbledon two years ago.
Venus Williams cruised to victory while Serena had a harder time, but both advanced to meetings with former champions.
Second seed Venus Williams rolled past fellow American Chanda Rubin, 6-3, 6-2, in under an hour. The reigning two-time Wimbledon and U.S. Open champion next takes on Seles in a rematch of their Australian Open quarterfinal battle in January.
The sixth-seeded Seles held off talented Slovakian teen Daniela Hantuchova, the 11th seed, 6-4, 7-5.
"Definitely it was such a close match," said Seles, who is 54-6 lifetime at Roland Garros. "Really, one or two points decided it. I was just really lucky, I think. I really was trying so hard to finish the match and tried just to concentrate really hard. I knew coming into the match it's going to be very difficult. She's been playing some great tennis. We're going to see a lot more of her winning these Grand Slams very soon."
In Melbourne, Seles defeated Williams for the first time in seven meetings to reach the semifinals.
"I just hope to play better than what I did in that match," said Williams, who lost to Seles in three sets. "I think whatever surface I play Monica on, I'm going to have to play well."
"I guess Venus will be up for revenge after the Australian Open," Seles said. "What else could I say about her? It's Venus. I know she has improved a lot on clay. Just the way Venus plays, she has a big advantage with her serve and movement over a person like me. So I have to neutralize with a few other things that don't give her that huge advantage in every service game."
Third seed Serena Williams reached her second straight French Open quarterfinal with a 4-6, 6-0, 6-3 triumph over Russian qualifier Vera Zvonareva. Williams dropped the first set in 47 minutes and saved a break point at the beginning of the second.
The 17-year-old Russian fell apart thereafter, losing the middle set in 25 minutes and lost her serve twice more in the third. Zvonareva, an accomplished junior, was playing in her first career Grand Slam.
Williams will play 2000 champion Mary Pierce of France in the quarterfinals. Pierce crushed ninth seed Silvia Farina Elia of Italy, 6-1, 6-2.