Nick Kyrgios has insisted he ‘stands by every word’ of his criticism of Jannik Sinner’s doping case, with the Australian tennis star saying he will lead the fight to save ‘the integrity of the sport’.

Sinner tested positive for the banned anabolic steroid clostebol during the Indian Wells tournament on March 10 and then again just eight days later.

The Italian was provisionally suspended but successfully appealed and was eligible to keep playing on the ATP tour while the International Tennis Integrity unit assessed all the evidence.

Sinner’s explanation for the banned substance entering his system was due to his physio Umberto Ferrara using a spray that contained clostebol to treat a wound on the tennis star’s finger.

The 23-year-old’s team explained Ferrara had purchased the spray in Italy, one of the few countries that allows people to purchase products containing clostebol over-the-counter.

An outraged Kyrgios immediately took to Twitter in the wake of the news, calling for Sinner to be suspended. 

‘Ridiculous – whether it was accidental or planned,’ Kyrgios wrote. 

‘You get tested twice with a banned (steroid) substance… you should be gone for 2 years.

Nick Kyrgios insists he ‘stands by’ his criticism of Italian tennis star Jannik Sinner

Italy’s Sinner was cleared of wrongdoing following a failed drugs test earlier this year

‘Your performance was enhanced. Massage cream…. Yeah nice’.

Kyrgios has since doubled down on his stance as he took to the commentary box for this year’s US Open.

‘Everything I put on social media I have to stand up for,’ he said on ESPN via Nine.

‘I’ve seen many of my friends go through doping things and being suspended. We’ve seen players like (Simona) Halep or Jenson Brooksby – players who’ve had their careers taken away from them.. it seems like every time one of these things comes up, there’s always a different process for different players.

‘I think he had it on his own terms for most of the time. I don’t think that’s fair and equal for the rest of the tours.

‘Every physio that’s employed by a player, as well as every player… we get sent a prohibited substance list every year.

‘On page five, it says ‘Prohibited at all times’. If there’s a clearing we need to get a definition of what ‘Prohibited at all times’ means. I’m pretty sure that means no matter what amount or if it shows up… that means you tested positive.

But outspoken Aussie tennis star Kyrgios said he would fight to save tennis’ ‘integrity’

‘Why is his team carrying a banned substance that we know is completely not necessary in the sport is another question itself.’

Kyrgios added that he has no issue with Sinner personally, but admitted he will struggle to look past the saga if they ever face on another on court. 

‘It’s nothing against Sinner personally at all. He’s one of the greatest tennis players we have right now. I’m not denying that. Nothing against him personally,’ Kyrgios said.

‘I’m definitely not going to be warm and hospitable like I was before. I just want a level playing field for everyone. That’s what this fight is for.

‘I got tested at my hotels two days ago. We do get tested consistently. This is a sport I’ve played my whole life. If the playing field isn’t the same for everyone, you kind of lose the integrity of the sport a little bit.’