Nadal has stomach muscle woe but advances, Serena rolls

NEW YORK (Reuters) - Rafael Nadal continued his march through the U.S. Open but an injury during Sunday's dominating victory may have signaled trouble down the road.

The powerful southpaw dominated childhood friend Nicolas Almagro 7-5 6-4 6-4 but called the trainers out to treat a nagging stomach muscle injury.

The extent of Nadal's injury was not immediately known though the Spaniard had missed Wimbledon to recover from tendinitis in his knees so his health was already in question.

While Nadal hopes to complete his career grand slam at the U.S. Open, 27-year-old Serena Williams is honing in on her 12th overall major and fourth at Flushing Meadows.

The second-seeded American marched into the quarter-finals by blitzing Slovak Daniela Hantuchova 6-2 6-0 in 64 minutes for her fourth consecutive straight sets victory.

"When she's playing like this, I don't think there's anybody that can beat her," lamented Hantuchova.

On the men's side, Spain's Juan Carlos Ferrero was leading 1-6 6-4 7-6 1-0 when Gilles Simon of France retired due to injury, while Chile's Fernando Gonzalez was a straight-sets winner over Czech Tomas Berdych.

Later, two-times champion Venus Williams was to play 2005 winner Kim Clijsters in a marquee fourth-round showdown.

MUSCLE STRAIN

All eyes at Arthur Ashe Stadium were on Nadal when the Majorca native called trainers over to help him with his stomach problem, believed to be an abdominal muscle strain he first suffered several weeks ago in Cincinnati.

At 2-1 down in the third set, Nadal had his stomach sprayed and taped. He grimaced several times but was able to complete his match and set up his fourth-round match against either Gael Monfils of France or Argentine Jose Acasuso.

"I will try my best to recover for my next match," the 23-year-old said in a courtside interview.

There was no denying the health of Serena's game.

"I thought it was good," she said. "I just want to keep this level and just stay focused and play well in my next match. Hopefully I'll be able to continue this."

Hantuchova said Serena's ability to play well on the game's biggest stage sets her apart.

"She's going to be one of the greatest (players ever) in the game. She's been able to always focus so well on the slams.

"You don't see her playing like this in a normal tournament that often. When it (a grand slam) comes, it brings the best out of her. That's what makes her a champion."

(Editing by Larry Fine)