Nadal, seeking his first US Open title to complete a career Grand Slam, will play on Saturday for a finals berth against Russian 12th seed Mikhail Youzhny, who outlasted Swiss 25th seed Stanislas Wawrinka 3-6, 7-6 (9/7), 3-6, 6-3, 6-3.

World number one Nadal reached his third consecutive US Open semi-final but has never reached the championship match, losing to Britain’s Andy Murray in 2008 and eventual winner Juan Martin Del Potro of Argentina last year.

“It was a very important victory,” Nadal said. “It’s a very nice feeling to be in the semi-finals third time in a row in one of the most important tournaments in the world, for me right now probably the most important.”

Nadal, 24, seeks his ninth career Grand Slam title and third in a row in 2010 after Wimbledon and the French Open. Only Roger Federer, Pete Sampras and Rod Laver have won three Slams in a row in the Open Era that began in 1968.

Swiss second seed Federer, a 16-time Grand Slam champion, and Serbian third seed Novak Djokovic meet in the other semi-final. Both were off Thursday but barring rain Nadal must win three matches in four days to claim the title.

“I have to play my best tennis,” Nadal said. “That’s the only way I’m going to get to the last round.”

In blustery winds, Nadal connected on 66 percent of his first serves and made only 16 unforced errors compared to 41 for Verdasco.

“Very difficult to play, one of the more difficult days,” Nadal said. “Serve was important. It was difficult to have big serves with the wind. When you throw the ball it was very difficult to control.”

Nadal has a 7-4 career record against Youzhny, but has won four of their past five meetings, most recently in the 2008 fourth round at Wimbledon.

Youzhny’s four triumphs over Nadal have all come on hardcourts, including a 2006 US Open quarter-finals upset.

“He’s number one. He won two Grand Slams (this year). He plays really, really well. It will be very tough for me,” Youzhny said.

“It will be a tough match, but I hope not only for me to be a tough match.”

The Russian could foil hopes for a Nadal-Federer final at the only Grand Slam where they have never played in the title match.

“I’m ready to be bad person,” Youzhny said. “I’d love to be bad person in this case.”

Nadal could join Federer, Andre Agassi, Don Budge, Roy Emerson, Rod Laver and Fred Perry as the only men to complete the career Grand Slam, but his concentration on the moment has kept him from pondering that possibility.

“I’m always focused on next match,” Nadal said. “I never look that far away.”

Nadal rolled into the last eight without surrendering a set or service game, having saved 13 break points and won 85 percent of first-serve points.

Nadal had won all 10 prior matches against Verdasco, including a five-hour 2009 Australian Open semi-final thriller in their prior hardcourt matchup, but looked in for a fight at the start in windy Arthur Ashe Stadium.

The showdown of left-handers began when Verdasco, seeking his first US Open semi-final, took the first service break of the tournament off Nadal to seize a 2-1 lead, Nadal netting a forehand to surrender his serve at love.

Verdasco, 26, saved a break point in the fourth game when Nadal sent a wind-blown forehand long. But Verdasco double-faulted away a break in the eighth game to draw Nadal level.

Nadal, who had dropped only three sets in 10 matches with Verdasco, broke at love in the 12th game to take the set, the last point on a forehand volley to end an extended rally.

Nadal, who improved to 106-1 in Grand Slam matches when he wins the first set, broke for a 4-2 lead in set two, pressured Verdasco sending a cross-court forehand wide on the pivotal point, and held twice more to win the second set.

“It was important for me to be focused all the time, moving the legs and waiting for the mistake of the opponent because it’s difficult to control the shots,” Nadal said.

The Spanish superstar, now 90-0 in Grand Slams when winning the first two sets, broke to begin the third set and held out from there to advance after two hours and 22 minutes.

US Open men’s singles quarter-final results

US Open men’s quarter-final matches on Thursday (prefix denotes seedings,:

*1-Rafa Nadal (Spain) beat 8-Fernando Verdasco (Spain) 7-5 6-3 6-4

12-Mikhail Youzhny (Russia) beat 25-Stanislas Wawrinka (Switzerland) 3-6 7-6(7) 3-6 6-3 6-3