New York ? Rafael Nadal rolled his head back, squeezed his eyes shut, covered his contorted face with his left arm and leaned awkwardly in the leather chair used by players during U.S. Open news conferences.

Frozen by the leg cramps that simultaneously hit his right hamstring and thigh about two hours after he’d won his third-round match, Nadal stopped taking reporters’ questions and paused between deep breaths to plead in Spanish, “Can you call a trainer for me, please?”

Then slowly — and scarily to those watching, because it was unclear at that moment to anyone but Nadal himself exactly what was wrong — the defending champion slithered out of the chair and went down to the ground, hidden from view by a table. Within minutes, Nadal was sitting up, and then standing, after being given bags of ice to soothe his painful leg and bottles of water and Gatorade to drink.

Even if it all amounted to nothing serious from a medical standpoint — as Nadal and his manager would later insist, chuckling — it was a bizarre scene, one at least as memorable as anything that took place on court Sunday at the year’s last Grand Slam tournament.

“It’s bad luck it happened here,” Nadal said, “and not in the locker room.”

His point was that tennis players often deal with cramps, particularly after competing in the sort of conditions Nadal did while beating 2002 Wimbledon runner-up David Nalbandian 7-6 (5), 6-1, 7-5 on a muggy afternoon with the temperature in the 80s.

“It’s just something that happens. It’s just unfortunate it happened in front of you all,” 2003 U.S. Open champion Andy Roddick told reporters after a straight-set victory over Julien Benneteau to get to the fourth round. “Every single player in there has had that happen before. Every single one. What we do — we run around, run miles and miles and miles and miles on the tennis court in nasty weather — (and) you throw nerves in there. I mean, it happens. As long as it doesn’t happen during a match, you’re fine.”

Roddick continued: “Cramps are fine. It’s not an injury. A cramp is a cramp. When you go to bed and your foot cramps, it’s the same thing.”

With No. 28 John Isner and unseeded Donald Young also winning Sunday, and No. 8 Mardy Fish advancing Saturday, Roddick is part of the first quartet of American men to reach the U.S. Open’s fourth round since 2003.