INDIAN WELLS, California (AFP) ― Rafael Nadal launches his Indian Wells ATP Masters title defense still feeling the sting of his loss to Stanislas Wawrinka in the Australian Open final.

“It was one of the toughest moments of my career,” said the world number one from Spain, who was hindered by a sore back in that four-set defeat by the in-form Swiss.

“It’s tough to be there for an hour and a half knowing you will not win. Not winning is not the most important thing ― the worst thing is knowing you will not compete.”

Nadal acknowledged that he didn’t know if he would have been able to stop Wawrinka had he been healthy, but it clearly still rankles that he didn’t get a chance to find out.

“I am a great loser, I never think about the losses, just a few hours then I forget and try to look to the next thing,” he said. “But it’s true that after that it takes a bit more time.”

Nadal has already regrouped with a clay court title in Rio de Janeiro two weeks ago.

Now he‘s hoping for a title repeat on the hardcourts in the southern California desert, where his triumph last year confirmed his return from a seven month injury absence. It was the first of four hard court titles that he numbered among the 10 trophies he won in 2013.

“It was a very emotional moment for me,” Nadal said. “It gave me more confidence that I was ready to be back, ready to compete.”

However, Nadal said 2014 is a new slate. Although his possible quarterfinal clash with Wimbledon champion Andy Murray was the talk of the men’s draw, Nadal said his most dangerous opponent was always the next one.

That will be Czech Radek Stepanek, who beat Uzbekistan’s Denis Istomin 6-1, 3-6, 6-1 Thursday to earn a shot at Nadal, who like all 32 men’s and women’s seeds in this combined ATP and WTA tournament enjoyed a first-round bye.