Rafael Nadal paid tribute to the retiring Andy Murray, saying the Brit would be a huge loss to the sport.

Murray, 31, announced on Friday he would call it quits in 2019 due to his troublesome hip, wanting to make it to Wimbledon despite accepting the Australian Open may be his last tournament.

Long-time rival Nadal, who has won 17 of his 24 meetings with Murray, became the latest to hail the outgoing three-time grand slam champion.

"Of course it's very bad news," the Spaniard told a news conference in Melbourne on Saturday.

"But being honest, when somebody like him, that he achieved almost everything in his tennis career, is suffering like he's done for such a long time already, and you feel that you are not competitive for the thing that really makes you wake up every morning and go on court with the passion to practice, to improve, and with a goal, then it's so difficult, no?"

"I can't say that because I didn't have that experience, but in some way I can speak about similarities that I had in my career. When you are going on court every day without the clear goal because you cannot move well, you have pain, then it's a moment to take a decision. Probably he is fighting to keep going since a long time."

"If he doesn't feel that the thing can go better, probably he does the right thing for his mental health. He will be a very important loss for us, for the world of tennis, for the tour, for the fans, even for the rivals that he has been part of a great rivalry between the best players for a long time, and a great competitor. But that's life."

"It seems like he had not a very long career because today players are playing that long. But he's 31 – 10 years ago, if he retired at 31, we will say he had a great and very long career. That's the real thing. So all the best for him. We will miss him. But today is him, tomorrow another one. We are not 20 any more. Our generation, everyone is more than 30. These kinds of things happen. That's it."

A winner of 45 titles on the ATP World Tour, Murray will bow out of tennis as one of the greats of his generation.

Nadal said Murray, a five-time Australian Open runner-up, should be proud of his career.

"Overall, when he puts everything on the balance, it will be that the positive things of the balance are much heavier than the negative things, even if in the end it's not probably the way that he dreamed about. But you can't manage that," he said.