Nadal enters Barcelona Open semi-finals

Top-seeded Spanish Rafael Nadal advanced to the Barcelona Open semi-finals with a hard-fought 4-6, 6-4, 6-3 victory over Finland's Jarkko Nieminen.

Nadal won his 45th consecutive match on clay on Friday to move within one victory of Bjorn Borg, second on the all-time list of consecutive games won, behind the 53 of Guillermo Vilas.

But Nadal, who last lost on the surface more than a year ago, trailed a set 4-1, before turning the tide against the 20th-ranked player in the world.

Nadal will aim to level Borg's mark from the 1970s when he plays the semi-final against compatriot Nicolas Almagro, who defeated former winner Juan Carlos Ferrero 6-3, 6-3.

"I knew I could lose - but I knew I could also win," said Nadal. "I have been in these situations before. The fans helped me a lot, Nieminen played very well."

"At times I was desperate. He was controlling the match early on, I had to fight my way back," he added.

It took nearly two hours for defending champion Nadal to salvage the win in front of his home crowd at the event.

In other matches, Stanislas Wawrinka became the only man this week to crack the huge serve of Ivo Karlovic, defeating the Croatian 4-6, 6-3, 6-4.

The more than two-metre tall Karlovic had been untouchable coming into this quarterfinal but dropped serve for the first time in four matches in the second set, as the Swiss Wawrinka took a 2-0 lead.

Wawrinka's confidence seemed to dent that of Karlovic, ranked 56 in the world, who was broken again in the final set as Wawrinka completed his comeback in exactly two hours.

The 21-year-old Swiss Davis Cup player next faces Tommy Robredo, who put out Czech fourth seed Radek Stepanek 6-3, 6-2.

The sixth seeded Robredo, the 2004 champion in Barcelona, first had to complete a rain-interrupted third-round contest carried over from Thursday night, beating Spain's Fernando Verdasco 6-3, 2-6, 6-2.

Wawrinka improved to 13-8 on the season, reaching his second semi-final of 2006 after Auckland in January, and third since joining the ATP tour.