* World number five to play Wawrinka on Sunday
* Spaniard chasing fifth title since return
* Wawrinka upsets Czech sixth seed Berdych (Adds result of second semi-final, Andujar quotes)
By Iain Rogers
MADRID, May 11 (Reuters) - Rafa Nadal is one win away from a fifth title since his return from injury after the Spanish world number five thumped compatriot Pablo Andujar 6-0 6-4 on Saturday to set up a Madrid Open final against Stanislas Wawrinka.
With his customary strapping on the troublesome left knee that sidelined him for seven months until February, Nadal was in scintillating form as he raced through the first set on the sun-drenched clay of Manolo Santana centre court.
Andujar, a tournament wildcard ranked 113 in the world, put up more of a fight in the second set but home favourite Nadal secured a fourth break in the ninth game and served out to move a step closer to his third title at the Masters event in the Spanish capital.
"The results could not have been better," he said in a courtside interview with Spanish television broadcaster La Sexta.
"Five months ago I could not have dreamed of everything that has happened during these past few months," added the 26-year-old. "It's almost a dream to be back in another final at home here in Madrid."
Wawrinka, the 15th seed, upset sixth-seeded Czech Tomas Berdych, runner-up last year to Wawrinka's Swiss compatriot Roger Federer, in Saturday's second semi-final.
It will be Nadal's seventh final appearance in seven tournaments since he returned, while Wawrinka arrived in Madrid fresh from his victory against David Ferrer in the final in Estoril last weekend, the 28-year-old's first title since 2011.
He has never beaten Nadal in eight attempts and lost to the Spaniard in the quarter-finals of the 2012 Monte Carlo Masters in their last meeting.
Nadal, the French Open champion, extended his spectacular winning streak in semi-finals on his favoured clay, his last defeat coming a decade ago when he fell to compatriot Carlos Moya in Umag.
Saturday's success against Andujar, who was appearing in his first Masters semi-final, was Nadal's 46th last-four victory on the red dust in a row.
The Majorcan is third on the list of clay title winners in the professional era with 39, trailing fellow left-handers Guillermo Vilas (45) and Thomas Muster (40).
He will be chasing an eighth French Open title and a 12th grand slam singles crown at Roland Garros starting later this month.
"Today I was facing the best player in the world," Andujar, who will jump to around 50 in the rankings by reaching the last four, told a news conference.
"With a player like him, when you have chances and you don't take your chances, afterwards, he does. He uses his chances."
Second seed Federer was upset by Kei Nishikori in the third round while world number one Novak Djokovic lost in the second round to Grigor Dimitrov.