Injured Following the completion of his Australian Open championship defense in the second round, Rafael Nadal claims he is "mentally destroyed."

The left hip issue that plagued Spaniard Rafael Nadal caused him to lose to American Mackenzie McDonald 6-4 6-3 7-5.

The 36-year-old said that while he had the ailment prior to the game, the discomfort had not been as bad as it is now.

"I really hope that it doesn't put me out of the court for a long time," Nadal said.

"It's not only the recovery. It's all the amount of work that you need to put together to come back at a decent level.

"I went through this process too many times in my career, and I am ready to keep doing it. I think, but that's not easy."

Speaking at his post-match news conference, 22-time Grand Slam champion Nadal said he felt he "cannot move" after his earliest exit at a Grand Slam since the 2016 Australian Open, when he was eliminated in the first round.

"[I] just can't say that I am not destroyed mentally at this time, because I will be lying," he said.

"Hopefully, it is nothing too bad. In the end [there] have been three positive weeks in terms of practice."

Nadal was trailing by a set and a break when he pulled up with the injury, taking a medical timeout towards the end of the second set before continuing.

He said he had considered stopping "all the time" but "didn't want to leave the court with a retirement".

"Just try your best until the end," added Nadal, who won his second Melbourne title 12 months ago. "It doesn't matter the chances that you have. That's the philosophy of the sport.

"That's the essence of the sport by itself. I tried to follow that during all my tennis career, and I tried of course to not increase the damage, because I didn't know what's going on."

This is the latest in a series of physical problems for Nadal, who admitted he had no feeling in his left foot during his victory at the French Open last year because of painkilling injections for the chronic injury.

He also withdrew from his Wimbledon semi-final last year with an abdominal injury he picked up in the previous match, and the same injury then hampered him at the US Open, where he suffered a fourth-round exit against Frances Tiafoe and appeared to injure his rib.

He said it was his love of the sport that keeps him going amid the injury setbacks.