Second seed Milos Raonic suffered a 7-5 6-4 defeat against Argentina's Carlos Berlocq in the quarter-finals of the Portugal Open.
Raonic, the world No 9, again disappointed on clay as he went down in 85 minutes to 62nd-ranked Berlocq.
The Canadian's usually reliable serve was broken four times and he also sent down four double faults.
"I want to do much better this season on clay than I have in the past," said Raonic. "I'm putting a lot of attention on Madrid (next week) and Paris.
"On clay, training doesn't mean a lot. You need confidence that only comes through wins."
Berlocq plays world No 98 Daniel Gimeno-Traver in the last four after the Spaniard upset his third-seeded compatriot Marcel Granollers 6-1 6-2.
Top seed Tomas Berdych had to come from a set down to book his place in the semi-finals.
Czech Berdych prevailed 3-6 6-4 6-4 against Argentine qualifier Leonardo Mayer and will take on Victor Hanescu for a place in the final after the Romanian dismissed home hope Gastao Elias 6-1 7-5.