The world number one triumphed in New York after beating Taylor Fritz in straight sets in the final on Sunday (08.09.24) and was delighted to secure a second Grand Slam triumph of the year after his build-up to the event was shrouded in controversy after it emerged that he twice tested positive for clostebol - a steroid that can build muscle mass - earlier this year.
Sinner said: "This title means so much because the last period of my career was not easy.
"It [the investigation] was and still is on my mind. It's not that it's gone, but when I'm on court, I try to handle the situation the best possible way.
"I'm happy how I handled this one. I'm just excited to have this trophy with me."
Sinner explained that he felt "more pressure" at Flushing Meadows than he did securing his maiden major at the Australian Open this year because he had entered the tournament under a cloud.
He said: "Here it was difficult because also the pre-tournament circumstances weren't easy.
"I felt like that I have grown, you know, match by match and that my confidence level went higher and higher at some point."
Sinner has won two majors and a number of other tournaments in a year in which he has suffered just five defeats but feels there is still room for improvement in his game.
He said: "So many big wins for me this season. Starting with Australia and playing so well there gave me confidence until now.
"The work never stops. I know I can still improve. As we saw today, a couple of things. You have to be proud of what you have. The rest, you have to go for it and work for it."