Sean Kearns, BBC Sport.
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.
Sinner was cleared of any wrongdoing after twice testing positive for low levels of a metabolite of clostebol – a steroid that can be used to build muscle mass – during the Indian Wells tournament in March.
The case was presented to a tribunal by the International Tennis Integrity Agency (ITIA).
The ITIA said its process was run according to Wada guidelines but respected its right to appeal.
Sinner was provisionally suspended but challenged the decision and was able to continue playing.
Sinner’s defence said he was inadvertently contaminated by the banned substance by his physiotherapist, Giacomo Naldi.
The ITIA accepted Sinner’s explanation that Naldi had applied an over-the-counter spray – widely available in Italy – which contained clostebol to treat a cut on his own hand.
The tribunal ruled that Sinner was not to blame, but stripped him of his ranking points and prize money for reaching the Indian Wells semi-finals.
He has since stopped working with Naldi. Sinner won the US Open in New York this month, 19 days after he was cleared.