New York ? Ah, what a little extra rest can do for a 33-year-old.

Andre Agassi was filled with so much pent-up energy, he jogged to the sideline at changeovers while his bedraggled opponent shuffled over, limping.

The oldest man ever ranked No. 1 took advantage of getting two days off during a rainy U.S. Open and reached the semifinals for the ninth time by beating No. 5 Guillermo Coria, 6-4, 6-3, 7-5, Friday.

“A lot of things get more difficult as you get older. Opportunities get rarer,” said Agassi, whose next opponent is French Open champion Juan Carlos Ferrero. “It wasn’t easy on anybody — the players, the fans, TV. It’s been a difficult week.”

Less difficult, though, for Agassi and Andy Roddick, who powered into his third Grand Slam semifinal of 2003 with a 6-4, 6-2, 6-3 win over No. 12 Sjeng Schalken. Roddick, whose season-high winning streak reached 17 matches, will play No. 13 David Nalbandian in the semifinals.

In the women’s semifinals Friday night, No. 1-ranked Kim Clijsters beat 1998 Open champion Lindsay Davenport, 6-2, 6-3, and No. 2 Justine Henin-Hardenne rallied to defeat No. 6 Jennifer Capriati, 4-6, 7-5, 7-6 (4).

Agassi finished his fourth-round match Tuesday when Taylor Dent quit after three sets because of a leg injury. And No. 4 Roddick booked his quarterfinal spot Wednesday.

The six other quarterfinalists played Thursday, setting up the possibility of four matches over the final four days at a major for the first time in the 35-year Open era.

“In a Grand Slam, it’s always important to have at least one day to rest,” the 21-year-old Coria said. “Agassi was kind of more rested.”

Lleyton Hewitt, the 2001 Open champion who lost to Ferrero Friday, said: “It’s a huge swing in Andre’s favor.”

Roddick’s response when told some thought it wasn’t fair that he and Agassi got time off? “Well, that’s too bad for them.”

As fresh as Agassi and Roddick looked Friday under a clear sky with temperatures in the high 70s, there was wear and tear all around them. ATP Tour trainers were busy, hustling out to attend to participants in all four quarterfinals.

Hewitt lost nine of the last 11 games against Ferrero after plopping down on the court to have his left hip massaged during a medical timeout. Hewitt also was treated a second time, and Ferrero won, 4-6, 6-3, 7-6 (5), 6-1.

Schalken needed his right leg massaged, and No. 22 Younes El Aynaoui’s left knee was sprayed and taped during his 7-6 (2), 6-2, 3-6, 7-5 loss to Nalbandian.

Coria was hampered by a sore left hamstring he picked up earlier in the tournament — plus an injury completely unrelated to the weather: He sliced his right thumb Friday morning when he reached into his racket bag and unwittingly grabbed a sharp tool used to cut foot calluses.

He wrapped it himself, found that uncomfortable, and took the tape off — producing specks of red blood on his white shirt until a trainer bandaged it.

Coria had other woes. One shot by Agassi midway through a 21-stroke rally looked long, and when the point ended, Coria walked over to the line judge and applauded, as if to say, “Thanks for helping him.”

Coria’s biggest problem was presented by Agassi, who dictated points much better than during a quarterfinal loss to the Argentine at the French Open in June.

“I wanted to make the match physical and make him step up and hit big shots consistently, and I did,” said Agassi, a two-time Open champion and runner-up to Pete Sampras last year.