Jannik Sinner says he is “surprised” by the World Anti-Doping Agency’s appeal against the decision to clear him of blame after he twice tested positive for a banned substance.

Wada said last month’s ruling by an independent tribunal to find the Italian had no fault or negligence was “not correct under the applicable rules”.

It has appealed to the Court of Arbitration for Sport (Cas) and said Sinner should be banned for “between one and two years”.

The 23-year-old said: “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.

“I knew it a couple of days ago, that they were going to appeal, that today it’s going to go official.”

Sinner was on court against Roman Safiullin in the last 16 of the China Open in Beijing when Wada’s appeal was announced. He beat the Russian 3-6 6-2 6-3 to progress to the quarter-finals.