Italian Sinner's triumph on home soil was the latest moment of glory in a near-perfect year in which the 23-year-old won eight tournaments, including his debut Grand Slam victories at the Australian and US Opens.

"It's amazing, it's my first title in Italy and it means so much to me," said Sinner.

"It's something very special. I just tried to understand what works best for each opponent, trying to play my best possible tennis. That was the key.

"It was a very high level tournament from my side. At times, I couldn't have played better, so I am very happy."

World number one Sinner again swept Fritz aside in straight sets just as he did in the group stage and the US Open final in September, improving his record on hard courts this year to 50-3.

Sinner is the first Italian to win the Finals, doing so days after becoming the first from his nation to top the ATP's end-of-year rankings.

His Tour-leading 70th win of the season made him the first player since Ivan Lendl in 1986 to win the tournament without dropping a set.

"I tried to make myself better than last year, to find the keys to win this final. I'm very happy to have handled this pressure and to share this success with the Italian crowd," said Sinner.

The first set went in Sinner's favour after an enthralling seventh game which lasted nine minutes and was eventually won on the fourth break point.

And despite Fritz's best efforts he couldn't fight back, failing to get a single break point in the second set and succumbing to his opponent's superiority.

Fritz fell short in his bid to become the event's first American champion since Pete Sampras in 1999 but will rise to a career-best of fourth in the rankings Monday.

"With the good results, it's been a great week for me," said Fritz, beaten for the fourth time in five meetings with Sinner.

"I want to congratulate Jannik and his team because he plays incredible tennis, really incredible."

Sinner has reacted to losing last year's final to Novak Djokovic by displacing the Serbian great at the top of the game, winning 26 of his past 27 matches.

However, he has been dogged by controversy after twice testing positive for traces of the steroid clostebol in March.

A World Anti-Doping Agency appeal against his initial exoneration has been hanging over his head since September, when WADA announced it was seeking a ban of up to two years.

Sinner now heads to Malaga where he hopes to lead Italy to a successful defence of their Davis Cup title.