The world number four enjoyed a stunning season, finishing as runner-up at Roland Garros and Wimbledon, winning her second career title in Dubai and then triumphing with Italy in doubles at the Olympics and again in Malaga.
Sinner, who lost last year's final to Novak Djokovic, did not put a foot wrong this time round as he finished undefeated and without dropping a set to earn $4,881,500 in prize money.
Spanish superstar Rafael Nadal is aiming to cap his emotional farewell from tennis with another Davis Cup triumph in Malaga next week.
Fifth-ranked Fritz triumphed 6-3, 3-6, 7-6 (7/3) over world number two Zverev in a thrilling match at the season-ending event in Turin.
World number four Daniil Medvedev said the ATP Tour calendar needs to be refocused around the Grand Slams and Masters 1000 events with the lower-tier ATP 250 tournaments moved to an optional slot later in the year.
The small furry objects that are the focus of every tennis player's energy are spinning the stars at the ATP finals into a fury and leaving them deflated.
Czech Barbora Krejcikova on Sunday called for respect and professionalism in sports media as she hit out at "unprofessional" remarks made about her appearance during a broadcast on the Tennis Channel.
Nadal, the winner of 22 Grand Slam titles, announced last week that he will retire from tennis after the Davis Cup Finals in Malaga next month.
When a teenaged Rafa Nadal bounced in to Roland Garros in pirate pants and sleeveless shirt in May 2005 before scything through the draw, few realised it marked the start of an unprecedented era of sporting domination.
Four-time Grand Slam winner Carlos Alcaraz made short work of China's Shang Juncheng on Saturday, defeating him in straight sets to breeze through to the Shanghai Masters third round.
Aryna Sabalenka said Tuesday that she wants to cap off a stellar year by returning to the top of the world rankings.
"I'm too far away from that level," he said. "I hope I'll reach it one day, but it's really impossible," said Alcaraz.
"It was a huge thing when I played him for the first time," said the world number three. "The other times for me were kind of a nightmare."
Tennis great Roger Federer said on Wednesday staying involved with the sport in retirement helped him avoid feeling "like an alien" ahead of this week's Laver Cup tournament in Berlin.
Jannik Sinner produced a brutal display of baseline power as he became the first Italian man to win the US. Open with a 6-3, 6-4, 7-5 win over American Taylor Fritz in the final on Sunday.
"I'm speechless right now. So many times I thought I was so close to get the US Open title. It has always been a dream of mine and finally I got this beautiful trophy," said Sabalenka.
Frances Tiafoe blamed his heartbreaking five-set US Open semi-final defeat to Taylor Fritz on cramping after his "body shut down".
The 23-year-old Italian is the only man to have made the quarter-finals of all four majors this season.
Top seed Swiatek, who won the title two years ago, showcased her all-court game in a straightforward 6-4, 6-1 win over Russian Liudmila Samsonova to open the evening session at Arthur Ashe Stadium and warned she was only going to improve.