NEW YORK (AP) - For two games, Martina Hingis looked exasperated playing tennis in the wind tunnel known as Arthur Ashe Stadium as shots flew as wildly as Wiffle balls in the breeze.

The top-ranked Hingis couldn't quite get a bead on the balls Anke Huber was sending her way, and she couldn't tame the shots she was sending back.

Hingis' befuddlement didn't last long, though, as she demonstrated her talent for adjusting to difficult conditions and outthink opponents. From 0-2, she won 12 straight games Tuesday to stroll into the U.S. Open semifinals with a 6-2, 6-0 victory.

Players have complained about the wind in the stadium since it opened two years ago. But the remnants of tropical storm Dennis have buffeted the court for several days, making this year's conditions the worst so far.

``She used the wind very well today to her advantage,'' said Huber, who lost to Hingis for the ninth time in 10 matches. ``She's just a very smart player, smarter than anybody else on the tour.

``The wind wasn't always against me, but it looked like it. I just overpowered the balls a little bit, made too many mistakes. It was very difficult because I play more aggressive than her. My shots are not as safe as hers. I thought maybe in these conditions, she's going to miss a little bit more, but she just didn't make any easy mistakes or any mistakes at all.''

Hingis eschewed modesty and agreed that she probably is the smartest player on the tour, at least when it comes to playing in the wind.

``Today I used the wind very much,'' she said. ``I was able to handle it better than her. She was getting frustrated with the serve. It feels like weightlifting when you play against the wind. You basically have no control if the other player is just as smart. I would take advantage of that.

``You learn it by experience. You don't get born with that thing. Some hit the ball hard, some don't. Some are tall. I have to use other weapons to stay at the top, otherwise I wouldn't be the No. 1 player if I wouldn't think a little bit on court.''

Injuries continued to plague the men's draw, already weakened by the loss of Pete Sampras and Mark Philippoussis before the tournament, as Magnus Norman became the seventh man to quit in midmatch.

Norman hurt his back and had to stop after losing the first set 7-6 (7-4) to No. 5 Gustavo Kuerten, allowing the 1997 French Open champion from Brazil to advance to the quarterfinals against Frenchman Cedric Pioline.

Pioline, who knocked off No. 14 Tommy Haas 6-4, 7-5, 6-3, reached the Open final in 1993 and at Wimbledon in 1997, but he has never won a Grand Slam tournament.

Norman hurt himself in the 11th game against Kuerten but tried to keep playing.

In the 11th game, the Swede raced to the net for a drop shot and flicked the ball crosscourt for a winner, pumping his fist as he broke Kuerten to 6-5. After the changeover, Norman was to serve for the set.

But when he got up from his chair to return to the court, he grabbed his back on the right side. He called for a trainer, who rubbed liniment on the right side of his back.

``It was not the last point when I broke him,'' said Norman, whose injury was diagnosed as a lower back strain. ``It was the point before.

``I felt a click in the back when I was going to return the serve at 30-40, the break point. I felt like just unbelievable amount of pain in the back. I thought this is something that is going to go over.

``But then when I came to the chair, I felt like, `This is not right.' I never felt like this before.''

Visibly hampered, Norman lost serve, sending the set to a tiebreaker. Kuerten just kept the ball in play, as Norman's shots went astray. The blustery, swirling winds also were no help, and Norman lost the tiebreaker 7-4.

``I tried to serve, but was no way. I mean, no chance,'' Norman said.

The trainer again worked on Norman's back, but the Swede returned to the court and quickly fell behind 15-30. Then he told the umpire he was finished.

``It's strange,'' Kuerten said. ``I thought he was really hurt. But sometimes players still can play very good tennis. I just put the ball back and he couldn't do anything with it.''

Norman, who won a tuneup tournament the day before the U.S. Open, was the second Swede to pull out with an injury during this year's event. Magnus Larsson retired from his third-round match with seventh-seeded Todd Martin.

Other men to retire were: Fabrice Santoro of France in the third round; Jan-Michael Gambill and No. 8 Carlos Moya in the second round; and defending champion Patrick Rafter, who was seeded fourth, and Julien Boutter of France in the opening round.