Sinner was aiming for a third successive Grand Slam triumph, having won the US Open at the end of last year and then defended his Australian Open title in January.
The 23-year-old’s level over the past fortnight – he arrived in the final having not dropped a set – was even more impressive considering he is still in the early stages of his comeback.
Sinner served a three-month ban from February to May after failing two doping tests last year and only played one tournament before Roland Garros.
“My level has improved since Rome. As I said before the match, my main goal was to see where it is at,” he said.
“Only making [the] final is difficult to accept now but this is the good part of the sport. Today I also had the sad part.
“But if you watch only the sad part, you’re never going to come back.
“I believe I have improved as a player since last year. We try to keep pushing.”
Sinner lost in a major final for the first time, having won all three of his previous trophy matches.