Novak Djokovic proved too strong for Andy Murray as he won a fifth Australian Open title in a punishing final.

The Serb, ranked number one, came through 7-6 (7-5) 6-7 (4-7) 6-3 6-0 in three hours and 39 minutes.

It was a third win over British number one Murray in a Melbourne final and brought him an eighth Grand Slam title.

Murray, 27, has now won two of the eight Grand Slam finals he has played in, having lost all four in Australia.

He will, however, return to fourth in the world rankings on Monday.

Murray had chances in each of the first three sets of the final but ultimately could not cope with the Serb's pinpoint returning and brilliant defence.

Djokovic, a week younger than his opponent, did look vulnerable at times, hurting his hand in a fall and appearing to struggle with an ankle problem early in the second set.

There were some concerned looks to coach Boris Becker in the stands and he required some energy-boosting fluids at a break down in the third set.

Murray was having his own problems, however, and just as at the US Open last September he could not keep pace physically with the Serb in the closing stages.

Djokovic had made a blistering start, racing into a 4-1 lead and going 20 minutes before he offered up a first unforced error.

It was to Murray's credit that he twice hauled back breaks to force a tie-break, but a double-fault at 4-2 and a loose volley at 5-5 simply gave Djokovic too many chances.

The four-time champion clinched it when Murray netted a return, before suffering an awkward fall chasing a net cord early in the second that required treatment to his hand.

Murray moved into a 2-0 lead but saw the advantage wiped out when a rejuvenated Djokovic strung together 13 straight points.

Again, Murray fought back, a forehand into the corner making it 4-4, and three break points were saved at 5-5 on the way to a second tie-break.

This time the Scot would not relinquish an advantage, winning a gripping rally to lead 5-2 and converting his third set point.

When Djokovic netted a forehand to drop serve at the start of the third set, Murray appeared to have finally gained the initiative after two-and-a-half hours.

It proved to be his last moment to savour, however. As fatigue took a grip, his second serve slipped from being vulnerable to a liability.

Djokovic was now winning 75% of those points, and a frustrated Murray was screaming "how many times" as his advantage fell away.

The Serb saw off one final moment of danger at break point in game seven, gesturing to coach Becker to become more animated, but he required no assistance.

Murray was a rapidly fading force, double faulting to drop serve at 5-3, and winning just 11 points in a fourth set that disappeared in under half an hour.

Djokovic celebrated by throwing his racquet into the crowd, while a furious Murray smashed his in despair.