ESPN Tennis

NEW YORK -- Rafael Nadal was treated for a stomach muscle problem during his third-round victory at the U.S. Open on Sunday.

The No. 3-seeded Nadal beat No. 32 Nicolas Almagro 7-5, 6-4, 6-4 in an all-Spaniard matchup.

Nadal already was comfortably ahead when both he and Almagro received treatment from trainers after the third game of the third set. Nadal had a patch applied to his stomach, while Almagro had his back worked on.

Nadal wouldn't discuss his health afterward.

"I don't want to talk about injuries," he said. "Sorry. No, no. I am a little bit tired to talk about injuries."

No. 2 seed Andy Murray had an easier time on Sunday, ending Taylor Dent's improbable run at the U.S. Open in the third round.

"Obviously the crowd wanted Taylor to win," Murray said, "but I played very well."

Trying to become the first British man since the 1930s to win a Grand Slam title, Murray beat the 195th-ranked Dent of Newport Beach, Calif., 6-3, 6-2, 6-2.

Murray is into the fourth round at a sixth consecutive major tournament. He was the runner-up at the 2008 U.S. Open.

Dent hadn't played at Flushing Meadows since 2005. He once was ranked as high as 21st, but he was told by doctors he might not be able to play professional tennis again after having three back operations.

"It's nothing but positive for me. This is a huge step forward in my progression," Dent said. "I'm glad to be back, but I'm sorry I'm not sticking around."

Nadal is a six-time major champion who is trying to complete a career Grand Slam by winning the U.S. Open.

This is his first Grand Slam tournament since the French Open, where he was upset in the fourth round, ending a 31-match winning streak at Roland Garros. He decided to skip Wimbledon, blaming tendinitis in his knees.

Nadal returned to the tour in August after about a three-month absence, and he appeared to pick up an abdominal injury then, although he pronounced himself fine when he arrived in New York.

Whatever the extent of his discomfort, Nadal played quite well against Almagro.

"I came here and I know everybody wants to talk about the injury," Nadal said at his postmatch news conference. "I really don't want to talk about that.

"I feel it a little bit now, but I'll try my best to recover for the next match. I'm here to work hard and try my best all the time."

[+] Enlarge

Timothy A. Clary/AFP/Getty ImagesRafael Nadal is treated during a 10-minute injury break early in the third set.

His next opponent, No. 13 Gael Monfils, advanced when Jose Acasuso quit because of left knee pain while trailing 6-3, 6-4, 1-0.

Murray's victory means 14 of the top 16 seeded men reached the fourth round -- the first time that's happened at the U.S. Open, and the second time at any major tournament. Only No. 5 Andy Roddick and No. 9 Gilles Simon aren't still around.

Murray, the runner-up to Roger Federer at the 2008 U.S. Open, made it into the fourth round for the sixth consecutive major tournament. He has said he wants to win a U.S. Open title, perhaps even more than he wants to win Wimbledon.

"I've always enjoyed the atmosphere. New York's one of my favorite cities," Murray said. "I came here the first time when I was 15 to play the juniors, and we got treated great here."

Sunday night's matchup pitted one of tennis' top returners (Murray) against an old-style serve-and-volleyer (Dent).

It wasn't even close.

"He doesn't miss. He really doesn't miss," Dent said. "I don't think that I served great tonight, but I don't think that I served poorly, either. But he made it look and feel like I served it underhanded out there sometimes."

He averaged 19 aces in his two victories at the Open -- and hit only two against Murray, who returned 60 of Dent's 68 serves into play. Murray accumulated 11 break points and converted six.

"I thought I returned really, really well," said Murray, who faces No. 16 Marin Cilic of Croatia next. "I thought that was the key to the match."

In other action, No. 24 Juan Carlos Ferrero, the French Open champion and U.S. Open runner-up in 2003, moved on when Simon stopped playing because of a right knee injury, while winners included No. 6 Juan Martin del Potro, No. 7 Jo-Wilfried Tsonga, No. 11 Fernando Gonzalez and No. 16 Cilic.

"Sometimes, I don't know why, I just feel a big pain," said Simon, who added that he's had problems with the knee since the French Open in May.

Simon stopped playing while trailing 1-6, 6-4, 7-6 (5), 1-0 Sunday.

Ferrero moved into the fourth round at Flushing Meadows for the first time since reaching the 2003 final. He missed last year's U.S. Open with a right shoulder injury.

Ferrero won the 2003 French Open and reached No. 1 in the rankings that year.

Information from The Associated Press was used in this report.