Toni Nadal has strongly defended Jannik Sinner over the world No 1’s failed drug tests and declared it is “unthinkable that he could act in an unfair manner.”

Nick Kyrgios labelled Nadal’s comments “ridiculous” and claimed the renowned coach would not have defended him if he was in the Italian star’s position.

It was revealed by The International Tennis Integrity Agency (ITIA) last week that Sinner had avoided a ban for failing two anti-doping tests in March as it was ruled he bore “no fault or negligence.”

Sinner tested positive for low levels of clostebol, a banned anabolic steroid, on March 10 and 18 — during and after the Indian Wells Masters.

The Italian received an automatic provisional suspension for each test, but he was allowed to continue playing after swiftly appealing to an independent tribunal for both instances.

The ITIA accepted Sinner’s explanation that the substance had entered his system “as a result of contamination from a support team member, who had been applying an over-the-counter spray (available in Italy) containing clostebol to their own skin to treat a small wound.”

Several players have been critical of the handling of Sinner’s case and suggested the 23-year-old has received special treatment compared to other players who have tested positive for banned substances.

Kyrgios has been the highest profile and most outspoken detractor, with the former world No 13 expressing doubts over Sinner’s explanation for how clostebol had entered his body.

In his column for El Pais, Toni Nadal weighed in on the Sinner saga and called out players “who have taken a stand against him.”

“It is absolutely clear to me that the Italian player does not want to commit any infraction, and even more so, not to seek any advantage through the use of prohibited substances,” wrote Rafael Nadal’s uncle and former coach.

“I know the player well enough to be able to say without a shadow of a doubt that he is one of the most correct and well-mannered guys on the circuit. For me it is unthinkable that he could act in an unfair manner.

“There was a problem within his team that he paid for quite dearly with the financial penalty and the loss of ATP points.

“It leaves me very perplexed how some of the press, instead of criticising the excessive sanctions of other occasions, now demands a similar punishment for the world No 1.

“It is not surprising that there are always people who take the right to speak and judge without fully knowing the case. It really amazes me even more that there are other tennis players on the tour who have taken a stand against him.

“I don’t understand how some of his colleagues who know him well, have trained with him and faced him in matches doubt his innocence or want a punishment against him that, strictly speaking, would be absolutely disproportionate.

“For the sake of a healthy society, in this case as in others, it would be appropriate to remember the phrase of one of the greatest writers of all time, Goethe: ‘Wickedness needs no reason, a pretext is enough.’”

In a reply to a post sharing Nadal’s quotes on X, Kyrgios hit out at the Spaniard and reiterated his stance against “cheating.”

“If this was me do you think Toni Nadal would come out and defend me? Players know that I ain’t about cheating. Ridiculous,” the Australian commented.

In a separate tweet, Kyrgios questioned why Sinner’s physiotherapist had not been relieved of his duties as soon as his team learned of the failed anti-doping tests.

“I’m just wondering as to why they waited five months to fire the physio? If they knew about it so early on,” asked the former Wimbledon finalist.

It was confirmed last week that physiotherapist Giacomo Naldi and fitness trainer Umberto Ferrara would no longer be part of the Sinner’s team.

Ahead of the US Open, Sinner expressed his appreciation for Naldi and Ferrara’s work, but conceded that the pair’s mistakes had been to blame for the failed tests.

“I want to start with [saying] that they have been a huge part of my career,” the world No 1 told the media.

“We made an incredible job, bringing a lot of success and then having a great team behind me. Now, because of these mistakes, I’m not feeling that confident to continue with them.

“I was struggling a lot in the last months. Now I was waiting for the result, and now I just need some clean air.”