-- By the time Roger Federer and Andre Agassi moved into a fifth set on a windy Thursday afternoon, it was as if they were playing an entirely different match than the one that was halted by Wednesday night's rains. The calm under the clouds of the previous night had given way to gusts that wreaked havoc on groundstrokes and serves, making the U.S. Open quarterfinal as much about resourcefulness as fitness.

In the end, it was the top-seeded Federer who showed more of both, outlasting the sixth-seeded Agassi, 6-3, 2-6, 7-5, 3-6, 6-3, to earn a berth in the semifinals against No. 5 seed Tim Henman.

Both Agassi and Federer had trouble adjusting to the wind, which gusted up to 40 mph at times.

"We couldn't play our games," Federer said. "Usually we are guys who look for the winner, you know, play aggressive. But we could not play this way, you know. So it did feel like two different matches."

No. 2 seed Andy Roddick, the only other American remaining in the men's draw, was ousted in the evening session 6-4, 6-4, 3-6, 2-6, 6-4 by Joachim Johansson.

The Roddick-Johansson match featured a pair of big servers, and every set turned on one service break. Johansson got the final break of the match, at 5-4 in the fifth, and it was decisive.

Johansson matched Roddick's 34 aces with 30 of his own, causing Roddick to drop his only sets of the entire tournament, using 141 mph rockets to knock out the defending champion.

Roddick dominated the third and fourth sets, winning 29 straight points at one point, but couldn't prevail in the end.

Johansson advances to meet No. 4 seed Lleyton Hewitt.

The wind forced players to completely alter their strategies depending on their side of the court. The conditions clearly affected Federer in the fourth set when he double-faulted three times in the eighth game, eventually leading to a break for Agassi.

"This is as bad as it gets," Agassi said. "I mean, I think anything sort of more than this, there would have to be some serious consideration into postponing matches. I mean, at some point, if chairs are starting to blow over, that's a problem."

Neither player seemed exactly sure where to hit the ball, with both trying to stay away from shots on the line, which invariably appeared to drift off to another location entirely -- often out.

"Today, hitting the ball in the dead center of the court was a great shot," Agassi said. "Literally, if the ball left my racket and was in play, it was my advantage. If the ball left his racket and was in play, he had the advantage in the point. . . . So it was the center of the court was the only shot to hit."

Federer's victory continues his quest to win three Grand Slams in the same year -- he has already taken the Australian Open and Wimbledon -- for the first time since Mats Wilander in 1988. But standing in his way will be Great Britain's Henman, a 6-1, 7-5, 5-7, 6-2 winner over Dominik Hrbaty on Thursday afternoon. Henman had been trailing Hrbaty 4-5 in the third set on Wednesday night when rain suspended their match.

Despite facing the same gusts of wind that disturbed Agassi and Federer, Hewitt swept through Tommy Haas on Thursday afternoon. Continuing the strong play that has enabled him to win his last two tournaments leading up the Open, Hewitt took out the resurgent Haas, 6-2, 6-2, 6-2.

Hewitt still has yet to drop a set in Flushing Meadows and has given up an average of just eight games per match thus far.

"You know, I felt good coming in," Hewitt said. "It's not going to get any easier, I know that, and especially going back-to-back Saturday, Sunday, if I can go through. But I haven't put a foot wrong just yet."

Andre Agassi waves to the crowd after his loss to top seed Roger Federer, who said, "We couldn't play our games."