For Sinner it is the end of a successful season in which he won his first two Grand Slam titles at the Australian Open in January and the US Open in September.
The 23-year-old, who also won the season-ending ATP Finals earlier this month, has lost just six of his 76 ATP Tour matches in the last 12 months.
In a press conference after her Davis Cup triumph, Berrettini described Sinner as “the most humble guy on the planet.”
However, Sinner's year was interrupted by an ongoing doping controversy that left him deserted The immediate future of sports is uncertain.
“Of course it’s a bit in your head,” Sinner said of the doping case.
“The most important thing is that everyone who knows me as a person trusts me – that's why I continued to play at the level I have.”
“I was a little bit down emotionally, a little bit heartbroken. Sometimes life gives you trouble and you just have to do it.” [deal with] It.”
Sinner looked exhausted when he was forced to a tie-breaker in the first set against Griekspoor, but came back even stronger towards the end of the second set, securing Italy's third Davis Cup triumph on his fourth match point.
Italy is the sixth team to win consecutive Davis Cup titles since the final tournament was introduced 52 years ago, and the first since the Czech Republic in 2013.
