Jannik Sinner says the doping case hanging over his season makes him feel “uncomfortable”, after the World Anti-Doping Agency (Wada) lodged an appeal against the International Tennis Integrity Agency’s (ITIA) decision to clear him of wrongdoing.

Sinner twice tested positive for the banned anabolic steroid clostebol in March.

The case was kept secret until August, when the ITIA announced that Sinner would face no consequences after his legal team argued to an independent tribunal that the world No 1 had been contaminated by his physio during a massage.

Sinner’s lawyers said that his fitness trainer purchased a spray “easily available over the counter in any Italian pharmacy” which was given to his physiotherapist, Giocomo Naldi, to help treat a minor cut on the physio’s finger. Naldi regularly massaged Sinner during the Indian Wells tournament without wearing gloves.

They claimed that because the player had “various skin lesions” on his body due to a skin condition called psoriasiform dermatitis, the spray – which contained clostebol – must have passed from the physio’s hands through to Sinner and caused the “inadvertent contamination”.

Last week Wada said it would challenge that verdict, and the case will now be settled in the Court of Arbitration for Sport.

“The finding of ‘no fault or negligence’ was not correct under the applicable rules,” Wada said in a statement. “Wada is seeking a period of ineligibility of between one and two years. Wada is not seeking a disqualification of any results, save that which has already been imposed by the tribunal of first instance.”

Despite the uncertainty over his future, Sinner reached the final of the China Open on Wednesday, where he was beaten by Carlos Alcaraz in a thrilling three-set match.

Jannik Sinner ‘uncomfortable’ as doping case clouds Shanghai Masters: ‘I thought it was over’

“It’s not in a situation where I feel comfortable in it, that’s for sure, because I thought it was over,” Sinner said ahead of his next tournament, the Shanghai Masters.

“It’s not easy. I had three hearings, which went my way, which was good, but now let’s see. But I’m very confident that it comes out very positively.”

Sinner’s immediate focus is on Shanghai, where he could well come face to face with Alcaraz once more.

The pair are yet to meet in a grand slam final, despite being the two outstanding talents of their generation. But a rivalry is beginning to brew on the court, and their final in Beijing this week suggested it could become one of the great duels of men’s tennis.

“We are quite similar as human beings off the court,” Sinner said of their relationship. “Obviously on the court we try to meet, we try to put on a big fight… he pushes me to do better, which is something good.”