Verdasco (25) is playing his first major semi-final while Nadal has already contested nine at the tender age of 22, winning all but two.

However, Nadal knows Verdasco is now transformed from the player he previously dominated on all surfaces and three continents.

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"It's always good to play against another Spanish player in the semi-finals of a Grand Slam," Nadal said.

"It's very good news for us. One (Spanish) player is going to be in the final. But Fernando is playing at his best level."

This "best level" includes shock defeats of World No4 Andy Murray and fifth seed Jo-Wilfried Tsonga, last year's runner-up, after breezing through the first three rounds for the loss of just 12 games.

Since sealing the Davis Cup for Spain in November, Verdasco has lost just once, in this month's Brisbane final.

"I never played against him when he's playing at this level like right now, because I think he never played at this level before, beating Murray, beating Tsonga," Nadal said.

"Sometimes in the past he had some mistakes in important moments and he lost a little bit of concentration. But right now he's changing these things.

"I think he played very well in Brisbane, but right now he's also playing well. I saw his two matches against Tsonga and Murray. He was very focused all the time, knowing what he wanted to do all the time."

Verdasco was coolness personified in his five-setter with Murray and he again showed nerves of steel in the quarter-finals, converting all four break points to send Tsonga crashing.

"Right now I'm believing so much about myself, about my game, I'm feeling pretty good, and I just think that I can beat anyone," said the 14th seed.

Verdasco said the Davis Cup final, when he subdued Argentina's Jose Acasuso and a baying Mar del Plata crowd over five gripping sets, was the turning point of his career.

Nadal missed the final with a knee injury, clearing the way for Verdasco to become Spain's new tennis hero.

"That Davis Cup changed my life so much and gave me a lot of confidence and mentally made me much stronger for these five-set matches here," Verdasco said.

"That tie in Argentina made me grow up a lot as a tennis player."

Verdasco hoped to draw on his close working knowledge of Nadal's game but admitted his stablemate was a daunting prospect over five sets.

"For me Rafa is the toughest player in five-set matches. It's the toughest match possible," he said.

"I know him, he knows me. I think that thing is there. And I don't think that's going to help me or not. I will just think about the match."

Nadal also said friendship would be put on hold in the all-Spanish semi-final, the Open's first in the professional era.

The Wimbledon and four-time French Open champion is bidding for a sixth Grand Slam title after reaching the semis for the second year running - and again, without dropping a set.

"The only difference is, we're both from Spain. We have a good very relationship. That's good, because one Spanish player is going to be in the final," Nadal said.

"So this is no different because in the end you're playing against a rival. This time the rival is another friend. But, anyway, it's going to be very tough."