By Alastair Himmer

MELBOURNE (Reuters) - Novak Djokovic stunned defending champion Roger Federer 7-6 7-5 6-4 to reach his second Australian Open final on Thursday after a match of high emotion which threatened to boil over.

"That's one of the best matches I've played," third seed Djokovic, who also knocked Federer out of last year's U.S. Open semi-finals, told reporters.

"I knew I had to take my chances. Second set I was 5-2 down. If I had lost that set God knows what direction the match would go."

Djokovic faces either Britain's Andy Murray, the fifth seed, or Spanish seventh seed David Ferrer in his fourth grand slam final on Sunday.


Federer choked when serving at 5-3 in the second set, a fired-up Djokovic roaring back to seize complete control of the match by crunching a double-fisted backhand down the line.

Serbia's Davis Cup hero broke for 2-1 in the third set, ruffling Federer, who not for the first time in the match spoke sharply to chair umpire Enric Molina at the changeover.

Federer, already upset about noise from Djokovic's box, then complained to his opponent across the net for the number of times the Serb was bouncing the ball between serves, to which Djokovic sarcastically replied, "Sorry."

If anything, Djokovic subsequently took more time between points but a dogged Federer clawed his way back to 4-4 with a threaded forehand down the line.

It proved only a temporary respite for the former world number one, who immediately surrendered his serve again, and Djokovic thumped his chest in delight.

The 23-year-old squandered two match points but finally closed out with a big serve Federer could only dump into the net after exactly three hours.

"It's obviously a bit of a blow," said Federer, who had been attempting to reach his 23rd grand slam final. "He played a great match. I was ready for another two sets -- clearly I couldn't push him there.

"I have no regrets I left everything out there."

(Editing by Ed Osmond)