World No 1 Jannik Sinner said the support and friendship he received from Jack Draper during his three-month ban for a doping violation gave him the positive energy he needed to make it through a difficult period.
Sinner accepted the ban following a settlement with the World Anti-Doping Agency in February after authorities agreed that the anabolic agent clostebol inadvertently entered his system through massages from his physiotherapist.
While some players raised questions about whether Sinner had received preferential treatment, Briton Draper stood by his fellow 23-year-old and the pair trained together ahead of the Italian Open where they are competing this week.
"We find ourself in a great friendship because we're very similar as people. We're humble. We try to do our best on court. Off court, we're very simple people," Sinner told reporters.
"His support meant so much to me. Whoever supported me in this period, I really appreciate that. It was positive energy."
Draper cracked the top five in the world rankings after winning at Indian Wells in March and making the Madrid Open final and is showcasing his clay credentials ahead of the French Open, which starts on May 25.
He beat Vit Kopriva 6-4 6-3 in Rome on Sunday before Sinner joined him in the last 16 with a 6-4 6-2 win over Jesper De Jong the following day.
"I've always been his biggest fan," Sinner said of Draper.
"When I can't play or when he's still in a tournament, I wish him only the best. Things are a bit more competitive now because he's in the position where he is, a top-five player.
"But it doesn't matter because off court, we have a great friendship. I'm sure we'll keep that throughout our careers."