The defending French Open champion, Nadal moved into the quarterfinals and extended his record clay-court winning streak to 57 matches by eliminating Hewitt 6-2, 5-7, 6-4, 6-2 Monday.
Hewitt had won their three previous meetings, but those were all on hard courts, the most recent in January 2005.
It was a different story at Roland Garros, where Nadal improved to 11-0 and moved closer to a showdown in the final Sunday against top-ranked Roger Federer.
''He's very much like Federer, winning so many matches that it's sort of second nature for him,'' Hewitt said.
Martina Hingis earned the last berth in the women's quarterfinals, beating Shahar Peer 6-3, 2-6, 6-3 in the completion of a match suspended overnight. Two unseeded men, Julien Benneteau and Novak Djokovic, earned their first Grand Slam quarterfinal berths, and No. 4 Ivan Ljubicic also advanced.
With a sun-splashed center-court crowd backing Hewitt's upset bid, the Aussie played Nadal on even terms for 2 1/2 hours, winning 11 consecutive points during one stretch. But at 4-all in the third set, Nadal broke serve with a typically inventive shot -- a backhand slice that barely cleared the net, landed on the sideline and bounced sideways as Hewitt chased it off the court in vain.
Nadal held at love to close the set and broke three times in the final set, repeatedly feasting on Hewitt's second serve.
''Late in the third and the whole fourth set, my serve did go off,'' Hewitt said. ''That made it a lot harder to put pressure on him.''
Nadal was coming off a grueling victory that took nearly five hours Saturday. But he looked like the fresher player at the finish, advancing in 3 hours, 17 minutes on the warmest day of the tournament.
And not once did Nadal choke on a banana -- a problem that forced an interruption for a visit from a doctor during his third-round marathon.
Joining Nadal on the men's schedule Wednesday will be Frenchman Benneteau, who advanced when Alberto Martin retired with a back injury trailing 5-1.
Ljubicic beat unseeded Ruben Ramirez Hidalgo 6-3, 3-6, 6-3, 6-2, giving Croatia two men's quarterfinalists at Roland Garros for the first time. Compatriot Mario Ancic advanced Sunday and will face Federer on Tuesday.
Djokovic defeated Frenchman Gael Monfils 7-6 (5), 7-6 (5), 6-3.
Hingis' opponent Tuesday will be two-time runner-up Kim Clijsters. It's a rematch of the Australian Open quarterfinals, which Clijsters won shortly after Hingis' return from a three-year injury layoff.
''I've made a lot of improvement since Australia,'' Hingis said. ''We'll see. Just got to come up with the best.''
A five-time Grand Slam champion, the No. 12-seeded Hingis is playing at Roland Garros for the first time since 2001. It's the only major event she has yet to win.
The 19-year-old Peer fell short in her bid to become the first Israeli, male or female, to reach a Grand Slam quarterfinal. But she gave Hingis some anxious moments.
After taking a 5-2 lead, Hingis hit a handful of shaky shots trying to seal the victory but did so when Peer hit errant backhands on the last three points.
''To be really scared of losing, she would have to be closer to be really totally scared,'' Hingis said.
She took charge by pinning Peer behind the baseline with deep groundstrokes, then moving to the net to close out points. Hingis won 24 of 29 points at the net, including eight of nine in the final set.
The match was suspended because of darkness after two sets Sunday, and resumed under a hazy sky to start the final week of the tournament. The first game was a 14-minute marathon, going to deuce five times before Hingis converted her third break-point chance.
Peer promptly broke back. Hingis regained the lead for good with a break at love for 3-2, and won 13 of 15 points for a 5-2 lead.
Martin stopped the match for seven minutes in the fifth game against Benneteau and received treatment from a trainer. He resumed play but was in obvious pain, hitting serves stiffly and not chasing shots by Benneteau, and finally conceded.
Martin said he has had back trouble in the past, and he aggravated the injury on a serve.
''I barely can walk,'' he said. ''I wish this would have happened in another tournament.''
Martin had reached the fourth round at a Grand Slam tournament for the first time in 31 major events. The unseeded Spaniard advanced in the first round when fifth-seeded Andy Roddick retired with an ankle injury.
Benneteau, ranked 95th, became the first Frenchman to reach the quarterfinals at Roland Garros since Sebastien Grosjean in 2002.
''On the spur of the moment, it's difficult to believe that the match is over and you've won,'' Benneteau said.
