The second-seeded Spaniard, who is 19-0 in his career at the French Open, has not dropped a set in the tournament this year. He next faces Novak Djokovic, who reached his first Grand Slam semifinal by beating Igor Andreev of Russia 6-3, 6-3, 6-3.

"I feel good," Nadal said. "I think I am progressing more as the tournament goes on. I feel a little better than last year."

Nadal, who lost to top-ranked Roger Federer on clay in the Hamburg Masters final, thinks he has become a better all-around player over the past year.

"I'm feeling better on court, more comfortable," Nadal said. "I feel I can play a little bit different: more aggressive, defensive sometimes."

Moya could not upset Nadal's rhythm.

"He was playing very deep, very high," Moya said. "Even when the ball bounces in the middle of the court, it bounces with so much spin it's difficult to attack him."

Nadal sensed Moya was struggling with his game.

"I played a little bit better and he had some mistakes with the backhand," Nadal said.

Last year at Roland Garros, Djokovic retired while trailing Nadal in the quarterfinals.

"He's the best player in the world on this surface," the sixth-seeded Djokovic said. "He plays with a lot of motivation and confidence. Physically he's very ready."

Nadal broke Moya in the fifth game of the first set to lead 3-2, but Moya broke back, setting up the chance with a drop shot.

Nadal won the final eight games of the match.

"After he won the first set everything was easier for him," Moya said. "It was going to be very tough to beat him."

Moya saved one match point with a backhand volley. He double-faulted to set up Nadal's second match point, which Nadal won with a forehand that Moya could barely get his racket on.

"I'm not very happy with the way I played today," Moya said.

Djokovic also had an easy time against Andreev.

"I was aggressive from the start and that was the key," Djokovic said. "The result is not showing the right picture about the match — it was not easy to play Andreev. He's the kind of player who makes you work for the points. He produces a lot of spin."

Nadal is 3-1 against Djokovic, but the Serb beat Nadal in the quarterfinals at Key Biscayne, Florida, in March.

"It's not the same match, it's not the same player," Djokovic said. "On clay you have to do more to try and earn the point against him."

"He's playing very good tennis," Nadal said of Djokovic. "He has unbelievable potential."

Djokovic leapt in the air when he went up 3-0 in the third set. The 125th-ranked Andreev could not find a way back, and Djokovic won on his first match point when Andreev hit a forehand into the net — one of many similar errors he made during the match.

"You keep winning matches, so you think you can do it," said Andreev, who beat third-seeded Andy Roddick in the opening round. "Unfortunately, today it didn't happen and I couldn't reach the semifinal. But I don't think it will be my last quarterfinal."

Andreev said Djokovic was strong in every aspect.

"He has no bad shots. He does everything very well," Andreev said. "Defending very well, serving very well. Mentally he is so strong for a young age."

The 20-year-old Djokovic took command early, winning five straight games from 3-3 in the first set to go up 2-0 in the second.

Djokovic beat Andreev on clay at Estoril, Portugal, last month, and went on to win the tournament — one of three titles he has won this year.

He becomes the third Serb to reach the semifinals. Jelena Jankovic and Ana Ivanovic reached the women's semifinals on Tuesday.

"Phenomenal for such a small country," Djokovic said. "Especially with no tennis tradition."

In the men's other semifinal on Friday, Federer will try to improve to 9-0 against fourth-seeded Nikolay Davydenko.