Switzerland's Stanislas Wawrinka claimed his first Grand Slam title in dramatic fashion on Sunday when he upset injury-troubled world number one Rafael Nadal in the Australian Open final.

The eighth seed roared through the first two sets and overcame the distraction of a back injury to Nadal, and then the loss of the third set, to take it 6-3, 6-2, 3-6, 6-3 in two hours 21 minutes.

Stanislas Wawrinka after winning the Australian Open. Pic/ AFP

Nadal, who was chasing his 14th major title, looked as if might pull out with the back injury but he fought back to take the third set and force the match into a fourth set.

"For me it's the best Grand Slam ever. I'm enjoying very much to play here," Wawrinka said, who lost in five sets to Novak Djokovic in last year's fourth round.

"In one year a lot has happened. Right now I still don't know if I'm dreaming or not. We'll see tomorrow morning."

It was a stunning win for Wawrinka, who had not beaten Nadal in their previous 12 matches but rallied to win the fourth set and take the championship.

He took 36 Grand Slam appearances to win his first title, second only to Goran Ivanisevic who played 48 before he won Wimbledon in 2001.