Top seed Albert Costa edged past Argentina's Gaston Gaudio 6-4 6-7 6-3 to reach the final of the Energis Open.
The French Open champion gained revenge for his loss to Gaudio in this year's Barcelona final and now meets another Argentine, Juan Ignacia Chela, in Sunday's final.
"Gaudio is a very complete player," said the Spaniard. "He's tough to beat and I'm very proud to be in the final."
Chela ended the run of unseeded Dutchman John van Lottum - playing in his first ATP semi-final - although he had to come from a set and a break down before sealing a 2-6 6-3 6-3 victory against the qualifier.
~~~Roger Federer (18 GS): Wimbledon 2003, AO 2004, Wimbledon 2004, US Open 2004, Wimbledon 2005, US Open 2005, AO 2006, Wimbledon 2006, US Open 2006, AO 2007, Wimbledon 2007, US Open 2007, US Open 2008, Roland Garros 2009, Wimbledon 2009, AO 2010, Wimbledon 2012, AO 2017 ~~~