By Larry Fine

NEW YORK (Reuters) - Andy Roddick fought his way to the quarter-finals of the U.S. Open after a season of injuries but the former winner crashed Friday, exhausted by his efforts and overwhelmed by defending champion Rafa Nadal.

"It was a combination of things that probably weren't going to work out today," lamented Roddick. "It was evident pretty early that he was in full control."

Roddick lost his first two service games to fall behind 4-0 and was broken six times in all by the second-seeded Spaniard, who rolled to a 6-2 6-1 6-3 victory.

The 29-year-old American, whose 2003 triumph at Flushing Meadows marks the last men's grand slam victory by a U.S. player, could not recover from his four-set victory over fifth seed David Ferrer Thursday.

Twice during the quarter-final he had his weary legs rubbed down by the trainer.

"I didn't have time to train this summer, so playing a tough match like yesterday I felt like I had played six sets.

"I just didn't have much."

Sidelined for much of the season by a shoulder injury and later an abdomen tear, the 21st-ranked Roddick has dropped from the top 10 for the first in nine years. Yet he rallied to get to the last eight at the Open before it all caught up to him.

"That's the most aggressive I've seen him play this summer. You know, he came out swinging," said Roddick.

Also falling in Friday's quarter-finals was fellow American John Isner, a four-set loser to Briton Andy Murray.

"There were a lot of good things," Roddick said about the U.S. showing at Flushing Meadows

"Men's and women's side. Especially from some of our younger players," he said, with a nod to Donald Young, who made the fourth round.

Roddick's futile struggle against the Spaniard silenced the center court crowd that usually spur him on.

"It's a bad feeling. You feel helpless," he said. "I think you'd rather be boo-ed than have silence. It's not fun."

(Editing by Ian Ransom)