GSTAAD, Switzerland -- Semi-retired Boris Becker, who has not won a tournament in two years, resumed his bid for his first clay-court title by beating defending champion Felix Mantilla 6-4, 6-4 Friday to reach the Swiss Open semifinals.
"I didn't expect to be in the semifinal," Becker said. "But as long as I practice and give myself a chance I am still a dangerous player. I've proven that in the past few days."
Becker is aiming for his 50th career title. His last one came at the 1996 Grand Slam Cup. Because of his limited schedule he is ranked No. 119, falling from the top 100 this week for the first time in 13 years.
In beating Mantilla, the No. 5 seed, Becker advanced to a semifinal for the first time this season.
The 30-year-old German will face top seed Marcelo Rios in the semis. Rios, ranked No. 2 in the world, defeated Spain's Francisco Clavet 6-3, 7-5 in his quarterfinal.
Becker's victory over Mantilla eliminated any possibility of Rios regaining the No. 1 ranking from Pete Sampras.
Rios, who has lost only seven matches in 1998 and briefly replaced Sampras at No. 1 this year, needed bonus points from wins over both Mantilla and Alex Corretja to reclaim the top ranking.
"It will be exciting to play Rios," said Becker, the winner of six Grand Slam titles. "I've played him a few times but not since he was world No. 1. Being a former No. 1 I will be able to compare him with other No. 1 players and see firsthand how good he is."
This is Rios' best showing in five appearances in this tournament. His best previous result were quarterfinal appearances in 1994 and 1995.
"I'm looking forward to trying to win this tournament," said Rios, who has won only one of three matches against Becker. "I want to be the best."
In a Spanish quarterfinal, Corretja, the No. 3 seed, rallied to a 5-7, 6-2, 6-2 victory over No. 6 seed Albert Costa, the 1996 champion.
Corretja, who lost to compatriot Carlos Moya in the French Open final, will meet Belgium's Filip Dewulf in the other semifinal. Dewulf won 1-6, 6-3, 6-4 to stop No. 8 Nicolas Kiefer of Germany.