Rafa Nadal came from behind to topple great rival Roger Federer 6-7, 6-2, 7-6, 6-4 on Thursday in an enthralling Australian Open semi-final of the highest quality.

Like so many of their battles over the years, their 27th clash was a feast of shot-making, with exhilaration and suspense served up in equal measure under the lights of a heaving Rod Laver Arena.

Amid an atmosphere more akin to a football match, Nadal's brute force triumphed over the Swiss's artistry as he captured the decisive break at 4-4 in the fourth set and closed it out on the second match point when Federer blasted a forehand long.

With raucous cheers ringing from the stands, Nadal tossed his gear at his chair after victory and slid out on to the blue centre court on his knees, leaning back to gaze at the night sky.

"It's always a pleasure being on this court," the world number two said in a courtside interview.

"It's an honour to play Roger. It was a fantastic match.

"It's just amazing to have one player in front of you who has no mistakes and a totally complete game."

Third seed Federer, just shaded on a night of high drama, had his chances to overhaul the Spaniard in the tension-charged fourth set but missed a break point when leading 4-3 and another two as Nadal served out the match.

The loss was Federer's second to Nadal on Rod Laver Arena, where he wept bitter tears after losing a five-set classic for the 2009 title.

"All of my career all I wanted to do was keep learning because there was one player in front of me," said Nadal who sealed victory in three hours and 42 minutes.

"If you told me that two Sundays ago (I would be here) I couldn't imagine it. For me it's a dream to be back in the final."

Nadal will bid for his second title at Melbourne Park against top seed Novak Djokovic or fourth seed Andy Murray, who meet in the second semi-final on Friday.

"I think both players are playing fantastic. I think my advice to Andy is to be aggressive, but my advice isn't very good because I lost the last six times against (Djokovic)," quipped the Spaniard.