Rafael Nadal has now won 17 straight matches and 42 straight sets on clay.
BARCELONA, Spain (AP) Rafael Nadal defeated Martin Klizan 6-0, 7-5 to extend his winning streak on clay and reach the Barcelona Open semifinals on Friday.
Nadal started well but needed to save three set points to close out the match for his 17th straight victory on the surface.
The top-ranked Spaniard has won 42 consecutive sets on clay.
''It was a good start for me, a quick one, but then in the second set everything changed,'' said Nadal, who had to come back from a break down. ''I feel a little bit luck today to be through in straight sets again.''
The 140th-ranked Klizan had eliminated Novak Djokovic in the second round.
Nadal will next face David Goffin, who defeated Spaniard Roberto Bautista Agut 6-7 (3), 6-2, 6-2. The 10th-ranked Belgian Goffin had to come back from a set down in all of his three victories in Barcelona.
In the other semifinal, Pablo Carreno Busta of Spain - who defeated second-seeded Grigor Dimitrov of Bulgaria 6-3, 7-6 (4) - will play against Stefanos Tsitsipas, the 63rd-ranked Greek who got past third-seeded Dominic Thiem of Austria 6-3, 6-2.
Nadal needs to win his 11th Barcelona title to retain his No. 1 ranking.