MELBOURNE, Australia -- Stan Wawrinka added a win over Rafael Nadal to his list of firsts in a stunning run to his maiden Grand Slam title, extending his rival's injury-cursed run at the Australian Open with a 6-3, 6-2, 3-6, 6-3 upset in Sunday's final.

The 28-year-old Wawrinka had never taken a set off Nadal in 12 previous meetings, but attacked from the start against the 13-time major winner and regained his nerve after dropping the third set against the injured Spaniard.

Nadal appeared to be on the verge of retiring in the second set, when he hurt his back and needed a medical timeout, but he refused to quit.

"It's really not the way you want to win a tennis match, but in a Grand Slam final I'll take it," said Wawrinka, the first man in 21 years to beat the No. 1 and No. 2 ranked players en route to a Grand Slam title.

Nadal was a hot favorite to win at Melbourne Park and become the first man to win each of the four Grand Slam tournaments twice in the Open era -- instead, his injury curse struck again. It remains the only major he hasn't won at least two times.

"Rafa, I'm really sorry for you, I hope your back is going to be fine, you're a really great guy, good friend and really amazing champion," Wawrinka said as he accepted his first major trophy. "Last year I had a crazy match, I lost it. I was crying a lot after the match. But in one year a lot happened -- I still don't know if I'm dreaming or not but we'll see tomorrow morning."

Wawrinka lost in five sets to Novak Djokovic in the fourth round of the 2013 Australian Open, in the longest Grand Slam match of the season. Djokovic went on to win his third consecutive title at Melbourne Park, and then beat Wawrinka again in five sets in the U.S. Open semifinals.