Melbourne: Defending champion Novak Djokovic was dragged into a rerun of last year's epic Australian Open final as he edged a gripping five-hour battle with Stanislas Wawrinka. (Agencies)
As women's number two Maria Sharapova enjoyed the smoothest progress in tournament history, it was a very different story in the men's competition as Djokovic was taken to five sets by the inspired Swiss.
Djokovic ripped off his shirt in celebration after finally clinching the 5hr 2min thriller at 1:41 am, evoking memories of last year's 5hr 53min final with Rafael Nadal, the longest Grand Slam title match in history.
But it is questionable whether the Serbian world number one, who now faces Tomas Berdych, will be in sufficient shape to seal the first hat-trick of Australian Open titles of the professional era.
"It's really hard to find the words to describe the feeling that we had tonight, especially in the fifth set," Djokovic said. "He (Wawrinka) deserves equally to be the winner of this match. It brings back the memory definitely of 12 months ago with Rafa."
Wawrinka, the world number 17, resembled his close friend Roger Federer as he smoothly ripped one-handed backhands on the way to breaking the stunned top seed three times in the first set.
Djokovic fought back to take the next two sets but Wawrinka clinched a fourth set tie-breaker to take it into a post-midnight decider in front of an excited crowd at Rod Laver Arena.
Both players exchanged early breaks in the nerve-jangling fifth set but the score blew out to 11-10 and both players were limping and wincing before Djokovic finally clinched it 1-6, 7-5, 6-4, 6-7 (5/7), 12-10.
Earlier Sharapova had no such problems as she clocked up her fifth 6-0 set score of the first week and blitzed Kirsten Flipkens 6-1, 6-0 to reach the quarters for the loss of just five games, smashing the tournament record.
Melbourne: Defending champion Novak Djokovic was dragged into a rerun of last year's epic Australian Open final as he edged a gripping five-hour battle with Stanislas Wawrinka.