He might have avoided a suspnesion from the International Tennis Integrity Agency following his failed drugs test, but the battle isn’t over yet for Jannik Sinner. The world No.1, who has risen to prominence in 2024 by winning both the Australian and US Open, seemed to have avoided a ban despite twice testing positive for clostebol during the Indian Wells Open in March.

The quantity of the banned substance in Sinner’s system was less than a billionth of a gram, and he argued the positive tests had been caused by contamination.

The Italian’s explanation that fitness coach physio Giacomo Naldi used the spray on his cut finger before issuing a massage to him was accepted by the ITIA, who duly cleared the star of any ‘fault or negligence’.

But during his last-16 match at the China Open on Saturday, the World Anti-Doping Agency announced they had appealed against the independent ruling. The case has now been taken to the Court of Arbitration for Sport (CAS), with Sinner now back at risk of a suspension.

In a released statement, the agency said: “It is WADA’s view that the finding of ‘no fault or negligence’ was not correct under the applicable rules. WADA is seeking a period of ineligibility of between one and two years.”

No date has yet been set for Sinner’s case to be heard by CAS. It means he could be waiting until early 2025 to learn his fate, although he is eligible to carry on competing in the meantime.

He doesn’t appear at risk of losing his US Open title though, or any of his tournament wins post-March. The statement added: “WADA is not seeking a disqualification of any results, save that which has already been imposed by the tribunal of first instance.”

Sinner has since expressed his shock at WADA’s stance, saying: Obviously I’m very disappointed and also surprised of this appeal because we had three hearings. All three hearings came out very positively for me.”

Amid the controversy, Sinner has seemingly retained his focus in Beijing. On Monday, he overcame Jiri Lehecka in straight sets to reach the semi-finals of the tournament he won in 2023.

Despite looking somewhat below his mercurial best, he dominated the first set 6-2. He then came through a tougher second set, but upped the ante when it mattered to take it in a tie-break.

He will now take on Yunchaokete Bu in the final four on Wednesday. The Chinese player, 22, has enjoyed a breakthrough tournament, beating fourth seed Andrey Rublev 7-5 6-4 in his own last-eight clash.