Andy Murray’s impending retirement was a decision he had to take because he is “suffering”, says long-time rival Rafael Nadal.

The 31-year-old Briton announced on Friday that he will quit this year, and next week’s Australian Open could be the final tournament of his career.

“When you are going on court without a clear goal because you cannot move well and you have pain, then it is the time to take a decision,” Nadal said.

“He will be a big loss for tennis.”

Nadal, 32, knows more than most players what it is like to battle injury having had a catalogue of serious problems over the years, with his knees and wrists in particular.

But the Spaniard, a 17-time Grand Slam singles champion, says he has never “arrived” at the point of feeling he had to quit the sport.

“I always had the feeling that we’ll fix it,” said the world number two, who begins his Australian Open campaign against home wildcard James Duckworth on Monday.

“But, of course, there are periods of time that you don’t see the light. It is tough.

“I know it is hard mentally. It is tough when you have one thing, then another thing.

“Andy has probably been fighting to keep going for a long time. If he doesn’t feel that the injury can become better, he has probably done the right thing for his mental health.”

Scotland’s Murray first met Nadal, who has won 17 Grand Slam titles, when they were teenagers and played against each other at junior tournaments.

The pair have met 24 times as seniors, with the Majorcan winning 17 of the contests.

“I always had good relationship with him,” said Nadal. “We shared moments in my academy. We shared courts in the most important stadiums in the world, competing for the most important things. That’s impossible to forget.

“So all the best to 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 kind of things happen.

“He will be a very important loss for us, for the world of tennis, for the tour, for the fans. 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 would say he had a great and very long career.”

British number two Cameron Norrie was beaten in his first ATP final, losing 6-4 6-2 to Tennys Sandgren at the Auckland International in New Zealand.

Norrie, who is ranked 93rd in the world, struggled playing in the city where he grew up before switching allegiance to Britain in 2013.

He was broken in his first game and made 29 unforced errors in the match.

American Sandgren is ranked 30 places higher than Norrie and eased to victory in 79 minutes for his first ATP title.

“He played a lot more solid and he didn’t really give me a chance to play well at all,” said Norrie.

“Throughout the tournament everything has just clicked. I’ve served and returned well. Today, there were a couple of areas and certain moments that I wasn’t quite there.”

Norrie will now move on to the Australian Open, which starts on Monday, where he will play American Taylor Fritz, whom he beat in the quarter-finals in Auckland.

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Andy Murray will not have wanted “to be making up the numbers” as he contemplated his future, says his former Davis Cup team-mate Tim Henman.

The three-time Grand Slam champion and former world number one will retire this year because of a hip injury.

And the 31-year-old Scot says next week’s Australian Open could be the final tournament of his career.

“It is sad news, but it doesn’t detract from what an incredible career he has had,” Henman told BBC Sport.

Former Wimbledon semi-finalist Henman, who has been friends with Murray since the Scot was a teenager, was one of many former players and fans offering their best wishes following the announcement in Melbourne on Friday.

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The two-time Olympic champion, who will play what could be his final ever game at approximately 07:00 GMT on Monday against Spain’s Roberto Bautista Agut, says he continues to be in “serious pain” as he tries to return following surgery on his right hip a year ago.

The operation came after he took six months off court following his 2017 Wimbledon quarter-final defeat by Sam Querrey in a bid to solve the problem.

Murray, who won Wimbledon in 2013 and 2016, says he wants to play at the All England Club this summer before retiring, but admits that might not be possible.

“It has been heading in this direction,” said Henman, who was replaced as British number one by Murray in 2006.

“I know how hard he has been working – I’ve been able to speak to him at different times and I’m close to Jamie Delgado [Murray’s coach].

“With the amount of work he has put in, and we know how professional and diligent he is, 20 months is a long time.

“And with the nature of the injury there were a lot of people who said this was going to happen at some stage.

“He will have ticked every box to give himself the best opportunity to play pain free at the highest level again.

“But the reality is he won’t be able to do that. In professional tennis terms he has seen there isn’t a fix for this hip problem.”

As well as adding the 2013 and 2016 Wimbledon titles to his 2012 US Open triumph, Murray finished runner-up in eight other Grand Slam finals, won the 2016 ATP Tour finals and guided Great Britain to the 2015 Davis Cup.

“When you look at the list of his achievements, there are no greater goals you can achieve in our sport,” Henman added.

“His development, from someone who joined us at the Davis Cup as a 16-year-old, and the way his game has progressed and the way he has matured physically and mentality, has been incredible to watch.

“I know he will be immensely proud of those achievements even though he will be disappointed at the moment.”

Henman, who reached four in the world, also struggled with injury in the final stages of his career – although over a much shorter period than Murray.

“I was very lucky when it came to my retirement and it really happened in the space of six or seven weeks where I was struggling with a number of different aspects,” he said.

“My back wasn’t brilliant at that stage. But also my form, the level of play I was playing at, wasn’t where I wanted, I wasn’t improving.

“And if you’re not improving, your ranking is going to go one way and I always believed I was playing in tournaments to win those tournaments.

“After Wimbledon in 2007 I started on the American hard court swing and felt for the first time I was making up the numbers.

“I felt that wasn’t what my career was about and I think Andy has said similar things.

“He feels he can play to a decent level but when he has been contending for Grand Slam titles and number one rankings he doesn’t want to be there making up the numbers.”

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Jamie Murray won his 23rd career doubles title at the Sydney International, defeating top seeds Juan Sebastian Cabal and Robert Farah 6-4 6-3 with partner Bruno Soares.

The win came a day after his brother Andy announced his plans to retire this year.

Murray and Brazilian Soares eased to victory in just 75 minutes.

They now head to the Australian Open, where they won their first Grand Slam title in 2016.

• Andy Murray can reflect on ‘incredible career’, says former team-mate Tim Henman