Andy Murray has revealed he has previously suspected his opponents of doping — the latest episode of the sport’s drug crisis.

Tennis headlines in 2016 have been dominated by drugs since Maria Sharapova confessed she had tested positive for banned substance meldonium at the Australian Open in January.

And while a reprieve, due to a technicality, looks possible for the highest-paid female athlete in world sport, her revelation has triggered significant debate on the issue.

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World No.2 Murray has been outspoken, calling for more tests and more investment in anti-doping measures, and his latest public comments are sure to set the tennis world talking.

Speaking to The Daily Mail, Murray revealed he has previously asked himself whether his opponents have been doping.

“I have played against players and thought, ‘They won’t go away’,” Murray said.

“Or ‘They don’t seem to be getting tired’. Have I ever been suspicious of someone? Yeah. You hear things.

“It’s harder to tell in our sport as people can make big improvements to a stroke or start serving better because they have made technical changes.

Sharapova was upset when announcing her positive test. Photo: Getty

“If it’s purely physical and you’re watching someone playing six-hour matches over and over and showing no signs of being tired, you’d look at that.”

Murray also spoke of training with American Wayne Odesnik, who was banned for importing human growth hormone in 2010, and then given a 15-year suspension in 2015 for another doping violation.

The Scot, who at the time of Odesnik’s second ban said it was “good that he’s off the tour”, said in this interview that in a 2010 training session, Odesnik’s upper body – he practised without a shirt – was “huge”.

Sharapova’s ban ‘positive’ for tennis

Murray, who again queried why the sport was not spending more on the doping program rather than prizemoney, thinks Sharapova’s ban has been good for tennis.

He took issue with the way the incident was handled, though, after Sharapova made her own announcement before authorities did, and thinks a change to those rules will help the sport.

“When someone like Sharapova is banned, I see that as being a positive,” he said.

“If someone is going through that process, the tennis world should let people know and, as far as I’m aware, they are changing that rule now.

“If someone is serving that suspension period or the period where they are arguing it or trying to come to conclusions what the sentence is going to be, that is going to become public knowledge.

Murray was frustrated throughout his clash with Nadal. Photo: Getty

‘So you’re not going to have silent bans or someone saying they were injured. That happened with Croatia’s Marin Cilic, where he pulled out of Wimbledon injured. People started talking and then it came out that he had failed a drugs test. And that looks terrible.”

‘I’m not stupid, Andy… you have zero respect for me’

Murray was involved in a war-of-words with umpire Damien Dumusois during a three-set semi-final defeat to Rafael Nadal at the Monte Carlo Masters at the weekend.

“It’s fascinating what you let some of these guys get away with,” Murray first said about his opponent’s apparent time-wasting tactics after the Spaniard levelled the match at one set apiece.

He then hit a tennis ball – softly – to Dumusois as he checked a spot in the clay-court surface.

“You have zero respect for me,” Dumusois said, before adding Murray had hit the ball at him twice.

“Don’t just make stuff up,” Murray responded.

The umpire retorted with: “You can disagree, but no respect, I cannot accept that. I’m not stupid, Andy.”