NEW YORK -- A long, rainy day turned into a short one for Andre Agassi.

The two-time champion moved into the U.S. Open quarterfinals Tuesday night when Taylor Dent quit because of a right hamstring injury with Agassi leading 6-7 (5), 6-4, 7-5.

It goes into the books as Agassi's 200th career Grand Slam match victory. If he wins the tournament, he'll tie Pete Sampras at 203, the third-most in the Open era behind Jimmy Connors and Ivan Lendl.

"To see him injured is outright disappointing for everybody. It doesn't matter if it's my 200th or first match. That's not way you want it to end," Agassi said. "It started to become apparent he was struggling with the leg. I was surprised he was unable to continue."

Their match was the first one that started and the only one completed because of off-and-on showers.

Top-seeded Kim Clijsters and No. 5 Amelie Mauresmo were sent home at 5 p.m., when their quarterfinal was postponed. Other singles matches pushed back until today: No. 3 Lindsay Davenport vs. No. 24 Paola Suarez, No. 2 Roger Federer vs. No. 13 David Nalbandian, and No. 7 Carlos Moya vs. No. 22 Younes El Aynaoui.

There also was another postponement: the retirement ceremony for Michael Chang that was supposed to be held between the night matches at Arthur Ashe Stadium.

The tournament referee's office was the site of the biggest buzz of activity Tuesday afternoon. Rain washed out big chunks of action for a second straight day, and officials said the tournament might not finish on time.

"The forecast right now is not all that optimistic," said Arlen Kantarian, U.S. Tennis Association CEO of pro tennis. He was talking about the weather, but he might as well have been referring to the logjam of delayed matches.

Shortly before 6 p.m., the top-ranked Agassi and unseeded Dent went out on the court to warm up. They played 34 minutes, long enough for Agassi to go up 5-4 in the first set, before rain returned and they walked off. A little more than an hour later, the match resumed, with Dent breaking right back to 5-5 and then winning the first set on a 109 mph second-serve ace while a misty rain fell.

During the changeover after the set, tournament referee Brian Earley came out to check the court, saying to Agassi and Dent: "If you guys both want to stay out here, we're willing." But eventually play was stopped again.

Then, at about 8:40 p.m., Agassi and Dent were playing the second set. It took nearly another hour, though, for matches to start on other courts, including Todd Martin against French Open champion Juan Carlos Ferrero, and No. 5 Guillermo Coria against Jonas Bjorkman. Crowds of 100-to-200 spectators were at those encounters.

When Agassi and Dent resumed, they traded service breaks early in the second set. That's when Dent began favoring his right leg -- which he originally hurt in practice a few days ago -- and was massaged by a trainer during two changeovers. He relies on a booming serve that can top 130 mph, but that speed dropped because he couldn't get a full push from his legs, and Agassi broke once more in the set's last game.

The third set opened with three consecutive breaks of serve, and at the initial changeover, a trainer wrapped Dent's right leg just above the knee. In the sixth game, a double-fault gave a break point to Agassi, who converted it to make the score 3-3 with a backhand return winner down the line that drew a nod of approval from Dent.

Serving while trailing 6-5, Dent double-faulted twice, and Agassi sealed the third set with a superb backhand return that Dent volleyed into the net.

Dent then walked over to the chair umpire and said he couldn't play any longer. Agassi came over to offer condolences, and Dent said, "It's OK. Good luck."

Shortly after they left the court, it was raining again, and action across the grounds came to a halt. Ferrero won the first set 6-2 against Martin, while Coria led Bjorkman 6-2, 2-0. Also, 2001 Open champion Lleyton Hewitt trailed No. 11 Paradorn Srichaphan 4-3 on serve in the first set, No. 15 Ai Sugiyama led No. 29 Francesca Schiavone 7-6 (5), 5-4, and No. 7 Anastasia Myskina led Mary Pierce 7-6 (2), 2-0.

Unlike at the Australian Open, there are no covered courts at the National Tennis Center for play or practice. Kantarian said a company that does stadium planning was recently hired to look into whether it would make sense to put a roof on Arthur Ashe Stadium. And unlike at Wimbledon, no tarps or tents are put on courts when it rains.

"We've been talking about covers since the '80s," Martina Navratilova said. "Yesterday they spent more time drying the courts than it rained. When are they going to learn? We have no say on it. Yesterday, it was two hours of play, six hours of drying. Fifteen minutes is enough after a drizzle."

So organizers were contemplating all sorts of contingency plans to finish the event by Sunday. But with a serious backlog, there is a chance the men's final could be played on a Monday for the first time since 1987.

Earley said one option would be to have players who have to finish a suspended match also go out later and play another full match on the same day. Asked whether men could be asked to play two full best-of-five set matches in one day, Earley said: "I never say 'Never."'

Martin, the ATP Player Council president, said players wouldn't do that, and he dismissed the idea of reducing men's matches to best-of-three sets.

"I don't remember seeing a 72-hole Grand Slam golf tournament condensed," he said. "To my knowledge, this facility is not needed for any other purpose next week. If we need to go to Monday or Tuesday, in my opinion, that's what we need to do."