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Associated Press
Britain's Andy Murray looks to make a forehand return to Serbia's Novak Djokovic during their semifinal at the Australian Open tennis championship, in Melbourne, Australia, Friday, Jan. 27, 2012. (AP Photo/Aaron Favila)

MELBOURNE, Australia — If anyone knows how Novak Djokovic feels after sweating and scrapping for almost five hours in the Australian Open semifinals, it's his next opponent — Rafael Nadal.

A day after Nadal beat Roger Federer in four compelling sets, Djokovic dug deep to overcome Andy Murray 6-3, 3-6, 6-7 (4), 6-1, 7-5 on Friday night after 4 hours, 50 minutes.

Defending champion Djokovic will face Nadal in a third straight Grand Slam final on Sunday. It's a reversal from three years ago, when Nadal had to regroup after his own lengthy semifinal.

The Spaniard needed 5 hours, 14 minutes in 2009 to get past compatriot Fernando Verdasco in the longest men's singles match in the tournament's history. He was so exhausted, he didn't lift a racket the following day.

Yet when the final rolled around, he beat Federer — who had an extra day to rest — in five sets that reduced the usually composed Swiss player to tears.

Now a weary Djokovic has less than 48 hours to prepare to face Nadal, one of the most fit players in the game.

"I know that I maybe have a mental edge because I've won six finals. … We played in 2011 and I've had lots of success against him," Djokovic said. "That's going to be my main priority and concern the next day and a half, to physically be able to perform my best and be ready to play five sets."

Djokovic won 10 titles in 2011, six of them by beating Nadal in finals. Just as Nadal has the mental edge over Federer, Djokovic has developed a hold over the Spaniard.

But the No. 1-ranked Djokovic has shown chinks in his armor at Melbourne Park this year. Against David Ferrer in the quarterfinals, he struggled to breathe through most of a straight-sets win and at one point, clutched his leg in agony.

Against Murray, he looked completely spent again when he hobbled gingerly back to his chair after dropping serve to go down 2-1 in the third set.

Murray had his own slump when he lost the fourth set in 25 minutes — an aberration in a match featuring long baseline rallies that quite often ended in errors.

One rally in the eighth game of the second set ended after 41 shots. The third set lasted nearly an hour and a half, with the opening game taking almost 15 minutes alone. There was one serve-volley point in the entire match, won by Murray.

When a scampering Murray knocked a forehand into the net on the final point, Djokovic collapsed onto the court, then shared a warm hug with his old friend Murray.

Djokovic will bid for his fifth major title on Sunday, with the chance to become only the fifth man in the Open Era to win three straight Grand Slam titles.