The world number one was dumped from the quarter-finals by his close friend and seventh seed David Ferrer in straight sets (6-4, 6-2, 6-3) to end his quest for a fourth straight non-calendar year Grand Slam victory.
Nadal appeared to injure his left hamstring in a drawn-out second game of the match, and sought several medical timeouts to continue.
He bravely stayed on court for over two-and-a-half hours, even though he was nowhere near his best, as Ferrer knocked out the world number one to set up a semi-final on Friday with last year's runner-up Andy Murray.
Nadal was not looking for excuses as he faced the media following his elimination, and preferred instead to laud Ferrer's performance rather than dwell on his injury misery.
"I can say nothing about the injury. Seriously, I would prefer I don't talk a lot about the injury," he said at the start of his news conference.
"First of all, I don't know nothing (about the injury), and secondly in respect to the winner and to a friend, I prefer to talk about the match.
"David played at a very high level. I congratulate him and wish him all the best for the semi-final.
"I think he's having a fantastic tournament. If he keeps playing like this, he's going to have a good chance."
Nadal, who arrived in Australia suffering the effects of a virus which hit him in Doha, said he didn't want to cultivate an image of blaming problems for his defeats.
"For me it is difficult to come here and speak about tonight," he said.
"In Doha I wasn't healthy. Today I have another problem. I seems like I always have problems when I lose, and I don't want to have this image.
"I prefer not to talk about that today. If you can respect that, it will be a very nice thing for me. Thank you."
Nadal said there were highs and lows in tennis, and the start of the new year had been a difficult for him.
"Last year I was very lucky. I was healthy for most of the year. I was playing unbelievable all the year," he said.
"This year I think I did all the right things to start the season playing really well.
"I was playing in the first exhibition in Abu Dhabi and after that the problem started. It was a difficult month for me.
"But it's part of the sport. I have to accept it, keep working and try my best in the next tournament. That's what I can do."
Nadal said he did not know what his next tournament would be.
"I don't know yet. I have to think a little bit about everything, and we will see what's going on in the next weeks," he said.
Nadal said he hated injury retirements, and had bad memories of his pull-out on the same Australia Day holiday at last year's Australian Open, during the third set of his quarter-final with Andy Murray, with knee trouble. He did not return to the tour until March.
"I hate the retirements. I did it here last year. I hate that moment. I didn't want to repeat that," Nadal said.