Nadal headlines Barcelona Open semis

World No.1 Rafael Nadal reached the Barcelona open semi-finals with a 6-0 7-5 victory over Martin Klizan, while potential rivals Dominic Thiem and Grigor Dimitrov crashed out.

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

Nadal was made to sweat by Klizan in the second set but the 10-time winner eventually triumphed and stretched his record to 42 consecutive sets on clay without defeat.

Klizan, ranked 140th in the world, knocked out Novak Djokovic in the second round and gave Nadal a scare when he led 5-3, but the Spanish star hit back strongly.

"He played very aggressively and caused me a lot of discomfort... he was unpredictable and that caused me confusion" Nadal told a news conference.

"It was tough, but the important thing was not to fail,."

Earlier, Stefanos Tsitsipas stunned Thiem with a comfortable 6-3, 6-2 victory, while Pablo Carreno Busta ousted second seed Dimitrov 6-4 7-6 (7-4).

Greek world No.63 Tsitsipas, 19 years old, eliminated the tournament's third seed in a surprising upset that demonstrated his credentials to be one of the next generation of tennis stars.

World No.7 Thiem made a total of 21 unforced errors in a surprising defeat which took little over 80 minutes and continued a string of high-profile eliminations, with Djokovic defeated and Kei Nishikori forced to retire after a wrist injury.

"I expected an even game but when it ended and I saw the result on the scoreboard, I was genuinely surprised," Tsitsipas said.

"The truth is that everything went well for me today."

Tsitsipas's triumph was a career best and he will face Carreno Busta in the final four on Saturday after the Spaniard's impressive triumph over Dimitrov.

This was Carreno Busta's third win over the Bulgarian, in six meetings, and it came in an hour and 37 minutes.

"My win over Dimitrov was important and it was about time that I had a good tournament in Barcelona," he said.

"I'm playing at my level, maybe now I have more experience and I'm doing well physically.

"I don't know [Tsitsipas]. I've seen him play and I know that they talk about him being a big player in the future.

"I will have to make him uncomfortable on the court."