MELBOURNE (AFP) — Rafael Nadal made history at the Australian Open a year ago when he won a then-record 21st Grand Slam crown, but his dispiriting defeat on Wednesday, Jan. 18, raises fresh questions about how much longer the ailing Spaniard can keep going.

Nadal's wife Mery was in tears at Rod Laver Arena as her injury-hampered husband succumbed 6-4, 6-4, 7-5 to 65th-ranked Mackenzie McDonald of the United States.

Nadal hobbled out of the arena, his hip sore and his title defense over after just two matches.

So what now for one of the best men's tennis players of all time?

In the short term, 36-year-old Nadal needs to diagnose and fix his hip.

In the aftermath of his physically and emotionally painful defeat, Nadal said he had the problem for "a couple of days" but did not know what the issue was.

"I don't know what's going on, if it's muscle, if it's joint," the deflated Spaniard told reporters.

"I have history in the hip that I had issues. I had to do treatments in the past, address a little. Was not this amount of problem.

"Now I feel I cannot move."

As far as Nadal is concerned, the future beyond that is clearer -- he says that he intends to carry on playing.

"From here on, I guess when things move forward, the right decisions will be made because what I want is to continue playing tennis," he said.

"Don't think I'm saying all this because I want to take a step back. It is not the case, but my current feelings are bad."

'We have to be realistic'

He may have been hindered by his hip against McDonald -- the latest in a long line of injuries that have blighted his career.

But even prior to this the signs were not good for Nadal that he would make it a 23rd major title in Melbourne, having won number 22 at Roland Garros last year.

Following that success at the French Open, Nadal pulled out ahead of his Wimbledon semifinal with a torn abdominal muscle.

At the US Open a few weeks later, he lost in the last 16 to Frances Tiafoe and went on to lose three more times towards the end of 2022.

The retirement in September of old friend and rival Roger Federer, albeit older at 41, brought Nadal's future in tennis into even clearer focus.

This year started no better for the Spaniard, with two defeats at the United Cup.

Nadal was then not at his best in his opener at Melbourne Park, needing four sets to defeat 38th-ranked Jack Draper, the young Briton who suffered cramps late in the match.

Speaking after his shock defeat on Wednesday, Nadal made clear that the injuries were taking their toll.

"It hurts as always, but in the end, the glass is getting fuller," he said in Spanish, a phrase that means getting fed up or reaching your limit.

"I've never been in a position to complain, life has given me so many positive things that I have no right to complain.

"But it is clear that things happen and at a sporting level the glass is filling up and there comes a time when the water can overflow.

"We have to be realistic."

If Nadal wins the French Open, his favourite tournament, again in May-June it would be his 15th triumph there.

It is the kind of round number that would make for a perfect send-off.