Rafael Nadal continued his clay-court domination with a 6-0 7-5 win over Slovakian qualifier Martin Klizan in the Barcelona Open quarter-finals.
The Spanish world number one extended his Open Era record to 42 successive sets won on his favoured surface.
Nadal, 31, will play compatriot Roberto Bautista Agut or Belgium's David Goffin in the last four.
Greece's Stefanos Tsitsipas, 19, beat world number seven Dominic Thiem 6-2 6-1 for the biggest win of his career.
World number 63 Tsitsipas punished an error-strewn display to set up a semi-final against Spanish world number 11 Pablo Carreno Busta, who also caused an upset by beating second seed Grigor Dimitrov 6-3 7-6 (7-4).