Rafael Nadal admitted on Wednesday he toyed with retiring injured against Mackenzie McDonald but chose to fight on instead in the second round of the Australian Open.

The top-seeded defending champion took a 6-4, 6-4, 7-5 loss to his 65th-ranked American opponent while dealing with a painful hip problem which has bothered him before.

“I considered stopping, but I didn’t ask the physiotherapist at the end,” Nadal said of his injury timeout in the second set.

“I tried to keep playing without increasing the damage. I was not able to hit the backhand at all. I was not able to run for the ball.

“But I just wanted to finish the match. That’s it.”

The Spaniard has suffered through dozens of injuries over his world-beating career but had been hoping to put up a solid defence of his title at Melbourne Park.

“I’m old enough to take my own decisions. I didn’t want to leave the court with a retirement.

“(It was) better like this at the end – I lost.

Rafa Nadal receives treatment as he loses his second round match. Photo: Roger Parker International Sports Fotos Ltd

“Nothing to say. Congratulate the opponent. That’s the sport: just try your best till the end.

“It’s been a couple of days like this, but nothing like today in that movement.

“I don’t know what’s going on, if it’s muscle, if it’s joint,” he said of his injury.

“I have a history of issues with this hip, I’ve had to do treatments in the past.

“But it was not this big of a problem – now I feel like I cannot move.”

Nadal said he will let doctors work out the details of the injury.

“But I”m tired of talking about this. I lost the match. That’s it. I tried until the end.”