Roberto Bautista Agut defeated defending champion Fabio Fognini 6-3, 6-4 to reach the final of the Mercedes Cup on Saturday.
The third-seeded Spaniard won almost three quarters of his service points and saved five break points in his victory over the top-seeded Italian in 1 hour, 14 minutes.
Bautista Agut was leading 4-1 in the first set when play was suspended for 40 minutes due to rain.
Fognini had been bidding to reach his fourth final of the season.
Bautista Agut, aiming for his second title following victory at 's-Hertogenbosch last month, will play either Czech Lukas Rosol or second-seeded Mikhail Youzhny of Russia in the final.
Youzhny won the tournament in 2002.