Melbourne: World No.1 Rafael Nadal shed tears during the Australian Open trophy ceremony following an emotional roller-coaster against Stanislas Wawrinka, and said a sudden back problem made it impossible to win the Grand Slam final.

The top seed was denied a 14th Grand Slam title by Swiss star Stanislas Wawrinka, who was crowned champion with a 6-3, 6-2, 3-6, 6-3 victory.

Nadal said he first felt a twinge during the warm-up, and the problem gradually got worse.

The World No.1 looked as if he might pull out after taking a medical timeout when falling a set and a break behind, but he fought back to take the third set and force the match into a fourth.

However, it was Wawrinka who held his nerve to come through and claim his first Grand Slam title.

It was a blow for Nadal, who has struggled in the past with injury at Melbourne Park.

He missed the 2006 and 2013 editions through injury, had to retire injured against Andy Murray in 2010, and in 2011 he was hit by a muscle strain during his defeat to David Ferrer.

Of his 13 Grand Slam successes, only one has come in Melbourne, in 2009, Sport24 reports.