Rafael Nadal took his clay-court win streak to 42 consecutive sets when he battled to a 6-0, 7-5 triumph over Martin Klizan in the Barcelona quarter-finals as he also moved just one win away from 400 on the surface.

World number one Nadal, the 10-time champion in Barcelona, was made to work by Slovakian qualifier Klizan, ranked at 140 and who had knocked out Novak Djokovic in the second round. Klizan had three set points to take the match to a decider but Nadal, who had been 3-5 down in the second set, battled back for victory on a third match point and will face Belgium's David Goffin for a place in the final.

"I went to the bathroom (after the first set) and maybe after that I lost some timing," said Nadal. "It was a great first set but I played a very bad game at the start of the second. It was tough -- I feel a little lucky to win in straight sets."

Should he prevail today, Nadal would become only the fourth man to win 400 matches on clay. The 31-year-old remains a long way behind all-time leader Guillermo Vilas of Argentina, who won 659 clay-court matches.

Compatriot Manuel Orantes won 502 while Austria's Thomas Muster racked up 422. However, Nadal has lost just 35 times on the dirt surface he has dominated for over a decade. He is also 56-3 for his career in Barcelona as the 16-time major winner builds up for an assault on an 11th French Open title next month.

"All these statistics, I don't pay much attention. If it happens, then that would be very good. But I only think of winning the match," said Nadal. "Now I am in another semi-final. That's great news but I will face a tough opponent. I need to be aggressive and play with the right intensity."

Goffin, the Belgian fourth seed, made the semi-finals with a 6-7 (3/7), 6-2, 6-2 win over eighth-seeded Roberto Bautista Agut of Spain. Goffin defeated Nadal in the World Tour Finals in London last year but the Spaniard has won both their meetings on clay, in straight sets in Monte Carlo and Madrid, also in 2017.

Nadal's hopes of winning the Barcelona crown for an 11th time were boosted earlier on Friday when two of his closest rivals, Grigor Dimitrov and Dominic Thiem, were knocked out. Second seed Dimitrov was defeated by fifth-seeded Spaniard Pablo Carreno-Busta 6-3, 7-6 (7/4).

Thiem, the third-seeded Austrian, was stunned by 19-year-old Stefanos Tsitsipas with the fast-rising Greek seeing off the world number seven 6-3, 6-2. World number 63 Tsitsipas won the last 14 points of the match to reach the semi-finals. It was his second win over a top 10 player following his victory over Goffin in Antwerp last October. He will face Carreno-Busta for a place in the final.