BEIJING, China (AFP) — Jannik Sinner said Saturday he was “very disappointed” but confident after the World Anti-Doping Agency (WADA) appealed the decision to clear him in his steroid case, seeking a ban of up to two years.

The Italian world No. 1 twice tested positive for traces of the banned substance clostebol in March but was exonerated and allowed to carry on playing.

The 23-year-old went on to win the US Open earlier this month for his second major crown, weeks after the International Tennis Integrity Agency (ITIA) found he “bears no fault or negligence.”

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

Clostebol is an anabolic agent prohibited at all times by WADA, who on Thursday appealed the high-profile case to the Court of Arbitration for Sport.

“It is WADA’s view that the finding of ‘no fault or negligence’ was not correct under the applicable rules,” it said in a statement on Saturday.

WADA made the appeal announcement as Sinner was on court at the China Open, where the defending champion fought back to beat 69th-ranked Russian Roman Safiullin 3-6, 6-2, 6-3 in Beijing.

“WADA is seeking a period of ineligibility of between one and two years,” it added.

Sinner has consistently denied knowingly doping and said after his win: “Obviously I’m very disappointed and also surprised.”

“We had three hearings. All three hearings came out very positively for me.”

In a statement released later on Saturday Sinner said that he had “nothing to hide” and bemoaned WADA’s decision “after the independent judges (from the ITIA) had exonerated me and deemed me to be innocent.”

He added: “They issued an in-depth judgement explaining why they determined me not at fault, with clear evidence provided and my cooperation throughout.”

“On the back of such a robust process both the ITIA and the Italian anti-doping authority accepted it and waived their rights to appeal.”

“It is difficult to see what will be gained by asking a different set of three judges to look at the same facts and documentation all over again.”

After winning the US Open, Sinner said that the controversy over his failed tests was still on his mind.

He defeated Taylor Fritz in straight sets to add the New York title to his Australia Open triumph in January.

“It was not easy, that’s for sure, but I tried to stay focused, with which I guess I’ve done a great job,” he said.

The decision to clear the Italian was met with scepticism by some players in the locker room who suggested that Sinner had benefited from preferential treatment due to his status in the sport.

Australia’s Nick Kyrgios said in a post on X that the lack of a suspension was “ridiculous.”