New York: Defending champion and second seed Rafael Nadal reached the US Open third round on Friday when his French opponent Nicolas Mahut quit with injury.
Nadal was 6-2, 6-2, 30-0 ahead when Mahut retired.
The Spaniard will tackle David Nalbandian for a place in the fourth round after the Argentinian defeated Croatian Ivan Ljubicic 6-4, 1-6, 6-3, 6-2.
Nadal had needed almost three hours to post a three-set win over Andrey Golubev in the first round and wasn't sorry to get off court quickly this time.
He said his 80 minutes against Mahut were enough to tell him he had managed to step it up in a few areas.
"I think I did a few things much better than in the first match," he said.
"I tried to to play with my strategy, tried to have the control of the point with my forehand, tried to play a little bit more aggressive when I had the chance, and I think I did."
Nadal bridled a bit at the suggestion that his game has dropped off significantly since he lifted the trophy here last year.
Although he won a record-equalling sixth French Open title in June, he has lost all five of his 2011 matches - including the Wimbledon final - to a surging Novak Djokovic.
He noted that he got off to a somewhat slow start at the US Open last year, and it was far from fatal.
"The people remember the last day when you are with the trophy, when you play fantastic in the final," he said. "But to arrive at this moment not everything is roses. You didn't play fantastic every match and every moment.
"Last year I didn't. I improved a little bit every day to win the tournament, and that's what happens thousands of times."