JANNIK SINNER’S coach has defended the world number one and suggested the investigation into his failed anti-doping tests led to his player missing the Olympic Games.

It was revealed on Tuesday that Sinner had failed two anti-doping tests in March but has been absolved of fault or negligence by the International Tennis Integrity Agency (ITIA).

The ITIA accepted Sinner’s explanation that the banned substance clostebol, an anabolic agent that can aid muscle growth, had accidentally entered his system via a product one of his team had used to treat a small wound.

Sinner was first told of his doping violation in April and, while he has won tournaments in Halle and Cincinnati, the Italian pulled out of the Paris Games after a bout of tonsillitis and his coach Darren Cahill feels the investigation had started to wear down the 23-year-old.

Cahill told ESPN: “I guess if you are not a Jannik fan, you may not see too much difference in what he has been doing the last few months because he has still been playing quite well.

“But if you are a Jannik fan, you would have seen a big change in his body language, physicality on the court, his excitement to be on the court – he’s struggled and I think it’s worn him down physically and mentally.

“He got tonsillitis, which is the reason why he missed the Olympics.

“I just want to stress that he’s maybe the most professional young man that I have ever had the chance to work with. He would never ever intentionally do anything and he’s in a situation that is incredibly unfortunate.”

Sinner first tested positive on March 10 while competing in Indian Wells and was red-flagged again in an out-of-competition test eight days later.

Both samples yielded trace amounts of clostebol but he was able to continue playing on the ATP Tour after successfully challenging a provisional suspension.

Scientific experts consulted by the ITIA concluded Sinner’s account — in which his physiotherapist had used an over-the-counter spray containing clostebol on his skin between March 5 to 13 — was credible.

Nick Kyrgios described it as “ridiculous” that Sinner had avoided a ban, while various other players have taken to social media to allege double standards with other similar cases.

Sinner has been stripped of the prize money and ranking points he gained at Indian Wells, where he made the semi-finals before a three-set defeat to Carlos Alcaraz.

“I will now put this challenging and deeply unfortunate period behind me,” Sinner said in a statement on Tuesday.

“I will continue to do everything I can to ensure I comply with the ITIA’s anti-doping programme and I have a team around me that are meticulous in their own compliance.”