Tennis legend Boris Becker has hit out at Andy Murray following his comments about doping in the sport.
The Scot was quoted in The Mail on Sunday saying he has competed against players at the highest level he has been suspicious of.
"I have played against players and thought, 'they won't go away' or ‘they don't seem to be getting tired'," quipped the two time grand slam winner.
“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.
"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."
Bekker, who is Novak Djokovic’s coach, responded to Murray, saying that his comments were ‘totally out of order’ and that players are tested too often to cheat the system.
"We have random drug-testing and unless it's proven, they are 100% innocent,” said the former world number one.
"So to assume something because somebody has won a grand slam or is fitter is totally out of order.
"Andy is one of the fittest players on the tour – he often outlasts players and nobody is questioning his ethics. I believe 100% Andy is clean. Roger [Federer] is clean, Rafa [Nadal] is clean, all these guys are clean.
"Novak gets tested a lot. That can mean twice in a Grand Slam."