Rafael Nadal extended his astonishing winning run on clay to 42 consecutive sets as he reached the semifinals of the Barcelona Open with a 6-0, 7-5 victory over Slovakia's Martin Klizan on Friday.

The defending champion will face David Goffin on Saturday after the Belgian beat Spaniard Roberto Bautista 6-7 (3-7), 6-2, 6-2.

Greek teenager Stefanos Tsitsipas also reached the last four after overwhelming third seed Dominic Thiem 6-3, 6-2 and the 19-year-old will next face Spain's Pablo Carreno Busta, who served up another upset by defeating second seed Grigor Dimitrov 6-3, 7-6, (7-4).

After romping through the opening set, Nadal lost his focus and surrendered his serve at the start of the second set. But just as world No. 140 Klizan appeared to be on the verge of delivering a psychological blow, the 10-time Barcelona champion saved the set point at 4-5 down before breaking back to level.

He held in the next game to take the lead for the first time in the second set and then broke a tired Klizan to clinch his place in the semis.

"He played very aggressively and caused me a lot of discomfort. . . . He was unpredictable and that caused me confusion. It was tough, but the important thing was not to fail," Nadal told a news conference.