Andy Murray on the road back to fitness, Maria Sharapova's return and his nerves watching his friend Anthony Joshua fight

Murray had much praise for Joshua after his stunning knockout victory over Wladimir Klitschko, although admitted he was so nervous he had to run out of the room

Murray was talking at a launch of this summer’s grass-court Aegon Championships (Getty)

Andy Murray is a big boxing fan but when Anthony Joshua beat Wladimir Klitschko to win the world heavyweight title he could hardly watch. Despite his love of the sport, Murray always has concerns for the boxers’ health, especially when he knows the fighters.

Murray, who first met Joshua five years ago, returned home from last week’s clay-court tournament in Barcelona on Saturday evening to find his family all ready to watch the fight on television. “I got in and my wife and mother and father-in-law were there and they were really pumped to watch the fight,” he said. “They were like: ‘Are you excited?’

“I shake when I watch boxing. My wife was like: ‘Are you OK?’ I had to leave the screen. I was unpacking my bag for 30 seconds, then I would come back and watch a little bit. I find it really difficult to watch, especially when I know someone who is in the fight. And because one punch can change the whole fight in the heavyweights, you are kind of on edge the whole time.”

He added: “I don’t get it watching fights where I don’t know the person. But if I’ve met them or feel like I know them a little bit, that’s probably been the case.

“The first time when I couldn’t actually watch the fight was when David Haye fought Klitschko. I bought the pay-per-view and stuff, a few of my friends came round and we had it on downstairs. I left the room after three rounds and checked my phones for the updates to make sure he was fine. I watched the fight back after it had finished. But watching it live, I find it hard.”

Murray was delighted to see Joshua defeat Klitschko (Getty)

Murray, who was talking at Queen’s Club at a launch of this summer’s grass-court Aegon Championships, said Joshua was a good role model.

“I met him the first time at the Olympics in 2012,” he said. “He doesn’t seem any different to how he was then. He maybe has a bit more of an aura now and is maybe a little bit more confident. But he doesn’t appear to have changed at all, which is refreshing.”

Murray has been impressed by Joshua’s appreciation of the need to work hard to stay at the top. “When you listen to him speaking and talking about his own career, he does appear to be very grounded and very aware of where he wants to get to and the best way of doing that,” Murray said.

Murray will return to Queen's Club this summer (Getty)

“Just from talking to him, I get the sense he has spoken to a lot of people in a lot of different sports. He went out to train with Klitschko [a couple of years ago] just to understand how to run a professional training camp.

“If you’re willing to learn and take on board the advice of people at the top of their sports, you’re going to understand quickly that the one common thing is that you have to work hard – all of the time. You can’t just be doing six months going out partying and then expect to just in a couple of months get yourself in great shape or turn up for the big events only.”

Murray said Saturday’s contest had been “an amazing fight, really exciting.” He added: “When you’re watching tennis and people say ‘that was an amazing comeback’, or ‘hugely brave’, there’s not really any comparison with what they’re doing. Both of them showed it the whole way through. Joshua was maybe just a bit fresher at the end and produced an amazing finish. Big respect for both of them.”

Murray will return to action at the Madrid Open (Getty)

As for his own year, Murray said he felt in much better shape than he had a few weeks ago, when he had an elbow injury. The Scot has made a modest start to 2017, though he won the title in Dubai. He lost to Albert Ramos-Vinolas in his first clay-court tournament last month in Monte Carlo but his form picked up in Barcelona, where he reversed the result against the Spaniard before losing to Dominic Thiem in the semi-finals.

“Barcelona was a really important week for me,” Murray said. “I played three matches in three days for the first time since Dubai and physically that was good for me because I also had the match with Ramos and that was a long one, three hours. That would have been the most that I would have tested my elbow and I was able to come back the next day and play a decent match against Thiem.

“I’ve done quite a bit of physical work the last couple of weeks as well. After I lost in Monte Carlo I did a couple of very tough sessions before Barcelona and then after I lost in Barcelona to Thiem I did a bike session straight after the match and I did a Versaclimber session yesterday, so I feel like physically I am getting back to where I need to be.”

The Scot progressed to the semi-finals of the Barcelona Open (Getty)

Murray, who will next play in Madrid and Rome before heading to the French Open at the end of this month, said his serve was the part of his game he particularly needed to improve.

“In the match against Thiem I got broken maybe six times,” Murray said. “I got broken seven times in my match with Ramos in Monte Carlo. Ramos obviously went on to make the final there, but I think if I am serving better, it gives me a much better chance. I haven’t been losing matches due to my return game. I’ve been breaking serve a decent amount, but I think against Thiem I won 54 per cent of my first serves, whereas last year my average for the season was in the mid to high 70s. That’s a huge difference.”

Murray turns 30 later this month but insisted: “I think I’ve got a good few years left in me. Physically, this year’s been a little bit of a struggle but at the end of last year, I was absolutely fine.”

Murray is attempting to win the French Open for the first time (Getty)

The defending champion at both the Aegon Championships and Wimbledon was asked about Maria Sharapova’s return to competition following her 15-month suspension. He thought her run to the semi-finals in Stuttgart last week was a good indication that she would return to the top.

Murray said that the French Open and Wimbledon could do “whatever they want” in terms of giving Sharapova a wild card, which would be quite within the rules but added: “The tournaments are going to do what is best for their event. I heard there was loads and loads of press [in Stuttgart]. Slams don’t need that.”

The Scot said there was “something to be said for working your way back up” and thought that Sharapova may well not need a wild card at Wimbledon because she would have earned enough ranking points by then to secure an automatic place in the main draw. If she has not done so, he thought it quite likely that Wimbledon would give her a wild card into the qualifying tournament.

“There’s a good chance that she can get in by right, which I’m sure is what she’s hoping for and that’s what Wimbledon would be hoping for, so they’re not in a position to have to make that decision,” he added.