It was revealed in August that the world number one had tested positive for the banned substance clostebol earlier in the year and the Italian admits that the case took its toll despite his confidence that he would avoid a suspension.

Sinner - who has been cleared of wrongdoing by the International Tennis Integrity Agency (ITIA) in a decision that faces an appeal from the World Anti-Doping Agency (WADA) - told Esquire: "It was a tough time.

"I couldn’t talk to anyone about it. I couldn’t vent or get help. All the people who knew me and watched me play understood that there was something wrong with me. I spent sleepless nights, because even if you are certain of your innocence, you know that these things are complex.

"Everyone immediately told the truth and that allowed me to play. But at Wimbledon, on the court, I was white.

"Even afterwards, my feeling with people was fearful. I went into training in the Cincinnati clubhouse and thought: ‘How are they looking at me? What do they really think of me?’ I realised who my real friends are."

Despite the doping controversy, Sinner still enjoyed the best season of his career so far as he won two Grand Slam titles and he says that his success hasn't come overnight.

He said: "I have grown so much this year, both mentally and physically.

"The results you see now are not sudden. They are the fruits of the hard work we have done over the past two years.

"I am the son of a chef, and I know that you don’t start cooking a good dish in a few minutes. You study, understand, try and try again - then the final dish will be good."