World No. 1 Jannik Sinner expressed on Friday that he was not in a "comfortable" situation as his doping case continues to unfold but emphasized that he feels prepared for his first match at the Shanghai Masters.

Last week, the World Anti-Doping Agency (WADA) announced its decision to appeal tennis authorities’ ruling that cleared the Italian player of any wrongdoing after he tested positive for a steroid twice in March.

Despite the ongoing controversy, the 23-year-old advanced to the finals of the China Open in Beijing on Wednesday, where he faced off against his archrival Carlos Alcaraz.

"It’s not in a situation where I feel comfortable in it, that’s for sure because I thought it was over... so it’s not easy," Sinner said when asked at a press conference if the pressure of the appeal was affecting him.

In August, the International Tennis Integrity Agency (ITIA) accepted Sinner’s explanation that the drug entered his system unintentionally when his physiotherapist used a spray containing it to treat a cut and then provided massage and sports therapy to the player.

But WADA said last Saturday it had appealed and was seeking a ban of up to two years.

"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 said Friday.

He now has to turn his attention to the Shanghai Masters, where he could end up facing Alcaraz again.

"We are quite similar as human beings off the court," Sinner said. "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."

Sinner will face Japan’s 93rd-ranked Taro Daniel in his first match of the tournament this weekend.

"I had my first practice session just now; I just finished, so I feel good. I feel recovered," Sinner said.