MADRID, Spain _ The U.S. reign as Davis Cup champion ended today, with a commanding performance by a player having a commanding year.

Buoyed by the cheers of a home crowd in a bullring, Rafael Nadal played the role of accomplished matador to the fullest, defeating Andy Roddick 6-4, 6-0, 6-4 to send Spain to the final for the sixth time.

Nadal, a master on clay, dropped to his knees and pumped his fists after giving his country an insurmountable lead in the best-of-five format.

"It's one of the nicest sensations you can experience in your career," he said.

Spain will play for the title in November against Argentina, which defeated Russia 3-2 in a semifinal in Buenos Aires. Juan Martin Del Potro beat Igor Andreev in the deciding match.

Nadal said he nearly didn't play Sunday because an MRI scan a day earlier showed a strained buttock muscle.

In the finale before 20,000 fans at Las Ventas arena, Feliciano Lopez defeated Sam Querrey 7-6 (3), 7-6 (4) in a match that had no bearing to complete a 4-1 victory.

Nadal was playing in Spain for the first time since capturing the top ranking. Nadal won the French Open, Wimbledon and the Olympic gold medal this year and ended Roger Federer's record 237 weeks at No. 1.

"It was one of my most emotional matches of the past few months," Nadal said. "This was a weekend I will always remember in my career."

Nadal also beat Roddick four years ago in Seville to help Spain land its second title.

"What Rafa did today deserves full credit," Spain captain Emilio Sanchez Vicario said. "He consumed every point."

Nadal picked Roddick apart with an array of shots. He broke Roddick five times, saved all seven break points and served eight aces. He won on his sixth match point by slicing a backhand winner across court from deep behind the baseline.

"I don't think you could draw up a tougher scenario than playing Nadal away in front of this crowd," said Roddick, who fell to 0-7 on clay against top-10 players. "It's probably the toughest match you can think of. Even Roger on grass, at least you can serve and the points are a little quicker."

Roddick, the 2003 U.S. Open champion who is ranked No. 8, was blanked in a set for the first time in 22 Davis Cup series. He fell to 0-5 in must-win Davis Cup matches and 0-4 against players ranked higher than he is. Known for his big serve, Roddick had only eight aces, with four coming in the next-to-last game.

"He's the best clay-courter of all time and I'm not that good of a clay-courter," Roddick said. "He wasn't leaving any balls short; he was kind of going for his shots."

Nadal and David Ferrer led Spain's sweep of opening singles Friday. The U.S., a 32-time Davis Cup champ, earned its point from Saturday's doubles victory by Mardy Fish and Mike Bryan.

Roddick ventured to the net but the strategy did not yield much against an opponent as savvy as Nadal, who has lost only twice in his past 117 clay matches.

"It was high risk, high reward," Roddick said. "I don't think there was much of a chance for me to sit back and trade punches with him from the baseline."

Nadal opened the semifinal Friday with a victory over Sam Querrey, a Davis Cup rookie who replaced James Blake, before David Ferrer rallied past Roddick in five sets. The Americans won Saturday's doubles, with Mardy Fish and Mike Bryan downing Lopez and Fernando Verdasco.

The U.S. had played 10 straight series with the same group, which was also missing Bryan's twin brother, Bob.

"It was a great Spanish team and a huge task coming here," U.S. captain Patrick McEnroe said. "I think we even made Rafa sweat a little bit on Friday. We walk out of here with our heads held pretty high."

On Sunday, Nadal set up a triple-break chance in the eighth game in the first set. He then hit a forehand down the line to break for a 4-3 lead. The crowd became charged up after Nadal rolled on the clay in vain to reach a drop shot.

In the 10th game, Roddick had a double-break chance. He flubbed the first one before Nadal delivered a forehand slam at the net, then closed things out with his third ace.

Roddick was exasperated after a 12-shot rally in the third game of the second set finished when Nadal hit a backhand into the corner. A return winner set up a double-break chance, which Nadal converted with a backhand.

Nadal caught the American going the other way with a volley to save a break chance in the sixth and Nadal closed the second set as he did the first — with an ace.

Roddick halted a seven-game slide by taking the opening game of the third set but could only let out a roar after Nadal saved a triple-break chance by the American, whose serve-and-volley approach was being picked apart by Nadal.

McEnroe offered only a chuckle to Roddick during the changeover with his player down 3-2 and the crowd chanting Roddick's name.

Nadal was unable to break Roddick one last time in the ninth game. The American saved five match points before Nadal eventually clinched the victory.

In Buenos Aires, Del Potro won the decisive match 6-4, 6-2, 6-1. Russia's Nikolay Davydenko had evened the score at 2-2 when he beat David Nalbandian 3-6, 6-3, 7-6 (2), 6-0.

It will be Argentina's third appearance in the Davis Cup final and its first as host. In 2006, Argentina lost to Russia, and in 1981 the team fell to the U.S.