NEW YORK — It’s as though Rafael Nadal never left.

If anything, he’s playing better than ever.

A year after skipping the U.S. Open because of a bad knee, the Spaniard powered his way back to the semifinals at Flushing Meadows, overwhelming 19th-seeded compatriot Tommy Robredo 6-0, 6-2, 6-2 on Wednesday night.

“I’m sure that’s the way I have to play to keep having chances to be successful in every surface, but especially on this one,” said the second-seeded Nadal, who is 20-0 on hard courts in 2013. “I was able to do it today. I hope to be able to do it in two days.”

On Saturday, Nadal will face No. 8 Richard Gasquet of France, who edged No. 4 David Ferrer of Spain 6-3, 6-1, 4-6, 2-6, 6-3.

That one took nearly 3½ hours, and was filled with plenty of ebbs and flows, allowing Gasquet to reach his first major semifinal in six years.

Nadal, meanwhile, was never challenged even the slightest bit by Robredo, who was coming off a fourth-round upset of 17-time Grand Slam champion Roger Federer. That stunning result scuttled the possibility of a Nadal-Federer showdown, which would have been the rivals’ 32nd meeting on tour but first at the U.S. Open.

The Nadal-Robredo match lasted 1 hour, 40 minutes, and it really was over after 22 minutes. That’s how long it took Nadal to dominate the first set, not only winning every game but also 24 of 29 points, including all seven that lasted 10 strokes or more.

The other two men’s quarterfinals are Thursday, with No. 1 Novak Djokovic of Serbia against No. 21 Mikhail Youzhny of Russia, and No. 3 Andy Murray of Great Britain against No. 9 Stanislas Wawrinka of Switzerland.

In the women’s semifinals Friday, No. 1 Serena Williams of the U.S. faces No. 5 Li Na of China, and No. 2 Victoria Azarenka of Belarus plays unseeded Flavia Pennetta of Italy.

Azarenka and Pennetta won their quarterfinals Wednesday. Azarenka, a two-time Australian Open champion and runner-up to Williams here last year, eliminated Daniela Hantuchova of Slovakia 6-2, 6-3.

Pennetta reached her first Grand Slam semifinal with a 6-4, 6-1 victory over 10th-seeded Roberta Vinci of Italy.