Switzerland's Federer, playing his first claycourt tournament of the year, needed just 55 minutes to brush aside Koubek and set up a final clash with Jarkko Nieminen of Finland.

Nieminen, the eighth seed in the $380,000 event, reached the final after Russian Yevgeny Kafelnikov retired injured in their semi-final.

Nieminen had won the first set 6-4 and lost the first game of the second set before the fifth-seeded Kafelnikov pulled out with a neck injury.

Federer, chasing his third title of the year after wins in Marseille and Dubai, has been impressive all week in the Bavarian city, suggesting he should be one to watch at the French Open starting on May 26.

"I didn't think it would be so easy," Federer said after outplaying one of his closest friends on the circuit.

"I concentrated on trying to make as few mistakes as possible and it worked out pretty well. I am a bit surprised to be playing so well on clay already."

Koubek, who had upset local favourite Rainer Schuettler in the previous round, looked helpless at times before bowing out by hitting a forehand wide on the first match point.

"I had a few break chances which I wasted and Roger played extremely well," said Koubek. "He was in a different league."

Nieminen, 21, has played in three finals in his career but is still waiting for his first ATP title.

"He's been looking really good this week," Federer, who is ranked fifth in the Champions Race, said of his final opponent. "I have to be careful."

The Swiss all-rounder, also 21, has played Nieminen twice previously, winning in straight sets both times.