Top seed Tomas Berdych ousted fifth seed Grigor Dimitrov in the pick of the day's quarter-final matches at the Stockholm Open.
In a rematch of last year's final in the Swedish capital, Berdych overcame a first-serve percentage of just 56 as he completed a 7-5 6-4 victory in 91 minutes.
The match was evenly contested, but Berdych managed to claim a crucial break in the 11th game of the first set and another in the ninth game of the second to dispatch his Bulgarian opponent.
Berdych moves on to face Marcos Baghdatis, after the Cypriot beat eighth seed Giles Muller 7-6 (7-5) 4-6 6-3.
The other semi-final will see American Jack Sock take on Richard Gasquet of France.
Sock eliminated third seed Gilles Simon 7-5 7-6 (7-5) in a tight two-hour encounter, gaining a measure of revenge for a defeat he suffered to the Frenchman in Rome earlier this year.
The 23-year-old fired eight aces and denied 13 of 16 break points faced.
"I'm happy to get through on my third match point and not have to stay out there any longer," said Sock afterwards. "I played more aggressive tennis in the middle of the second to get it back. With my style I try to come forward as much as I can and I was able to do that there at the end of the second."
Second seed Gasquet, meanwhile, defeated countryman Jeremy Chardy 2-6 6-3 7-6 (7-4), battling back from a set down to prevail after two hours and 13 minutes.