Mayer hadn't beaten any players in the top 30 since last year's French Open, where he beat American James Blake in the first round.

Mayer converted just three of his 24 break points before closing out the match in 2 hours, 55 minutes.

In his second career semifinals, the 59th-ranked Mayer will meet second-seeded Fernando Verdasco of Spain, who struggled to beat Sergiy Stakhovsky of Ukraine 6-2, 6-7 (5), 6-4.

Verdasco won his second title of the year at Barcelona last month and is considered a contender to make a deep run at the French Open, which starts Sunday in Paris.

Stakhovsky broke immediately in the third set and went up 3-1, but Verdasco broke back and finished him off.

"I finished the match playing very well, although I had a problem with my arm," Verdasco said. "It worries me because I have Roland Garros next week and you don't like to have this kind of problem three or four days before a Grand Slam."

Third-seeded Gael Monfils of France lost 7-6 (2), 6-2 to Potito Starace of Italy, who beat him for the third time in four meetings on clay.

Starace will play his second semifinal this year, against another Frenchman, Richard Gasquet, who downed Olivier Rochus of Belgium 6-4, 6-2.

A former top-10 player, Gasquet is looking to get back to his best after his career was hit by a suspension last year for testing positive for cocaine. The Frenchman won the Bordeaux challenger last week and was on an eight-match winning streak.