Jannik Sinner has revealed he struggled to sleep when facing the threat of a doping ban earlier this year, saying the episode made him realise who his real friends are.

It was announced in August that Sinner had twice tested positive for Clostebol – a banned performance-enhancing steroid – at Indian Wells back in March.

The world number one was subsequently cleared of any wrongdoing by an independent tribunal, which found he inadvertently took Clostebol when using an over-the-counter treatment given to him by his physiotherapist. 

The World Anti-Doping Agency (WADA) has appealed against that decision, but Sinner has repeatedly expressed confidence he will avoid any punishment.

Nevertheless, he struggled in the aftermath of his positive test, which he feared would turn his fellow professionals against him.

"It was a tough time," Sinner told Esquire. "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 had 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."

Aside from the positive test, Sinner enjoyed a stellar 2024, winning his first two major crowns at the Australian Open and US Open while also triumphing at the ATP Finals and helping Italy retain the Davis Cup.