Novak Djokovic says the doping case involving men’s world No 1 Jannik Sinner “is not helping tennis at all”.

The World Anti-Doping Agency (WADA) said it was seeking a ban of up to two years after Sinner twice tested positive for traces of the steroid clostebol in March.

The International Tennis Integrity Agency (ITIA) had cleared the Italian of wrongdoing in August, and weeks later he won the US Open.

The ITIA accepted Sinner’s explanation that the drug entered his system when his physiotherapist used a spray containing clostebol to treat a cut, then provided massage and sports therapy to the player.

The appeal to the Switzerland-based Court of Arbitration for Sport (CAS) means that the case might not be resolved before Sinner begins his defence of his Australian Open title in January.

Djokovic – speaking ahead of this week’s Shanghai Masters where Sinner is the top seed – said that tennis has “a system that is not working well”.

“Well I think it’s quite obvious that we have a system that is not working well,” said the 24-time Grand Slam champion. “So I guess that’s probably something that, even people who are not following our sport, are realising.

“There are way too many inconsistencies, way too many governing bodies involved and just this whole case is not helping our sport at all. And I think he has won the three appeals so far that he had and it must be very tough for him and his team and family.

“Hopefully we can go back to tennis and it’s impressive what he’s been doing in the whole process of what’s been happening, that he’s been playing at such a high level, winning a Grand Slam and winning most of the matches that he plays.”

Sinner ‘confident’ of avoiding doping ban

Speaking ahead of the Shanghai Masters, the Australian and US Open champion said the lingering case has been taxing.

“I’m very confident that it comes out very, very positively,” he said of his chances to avoid a ban. “But it’s not in a situation where I feel comfortable.

“I’m still surprised but I will collaborate like like I did before. I had three hearings in which they all went my way. It was good but now let’s see.

“I would be very, very surprised if it would be the opposite side. I thought it was over so it’s not easy.”

Sinner can continue playing while the appeal is being heard.

What’s coming up on Sky Sports Tennis in October?

• Shanghai Masters – ATP 1000 (October 2-13)
• Wuhan Open – WTA 1000 (October 6-12)
• Almaty Open, Kazakhstan – ATP 250 (October 14-20)
• Stockholm Open, Sweden – ATP 250 (October 14-20)
• European Open, Antwerp – ATP 250 (October 14-20)
• Japan Open, Osaka – WTA 250 (October 14-20)
• Ningbo Open, China – WTA 500 (October 14-20)
• Erste Bank Open, Vienna – ATP 500 (October 21-27)
• Swiss Indoors, Basel – ATP 500 (October 21-27)
• Guangzhou Open, China – WTA 250 (October 21-27)
• Toray Pan Pacific Open Tennis, Tokyo – WTA 500 (October 21-27)

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