Italian Sinner arrives in Turin at the end of a sensational season in which he was victorious at the Australian and US Opens -- his first Grand Slam triumphs -- and won five more ATP titles.
The 23-year-old is seeking a first ever title at the season-ending tournament in Turin and has come a long way since losing last year's final to Novak Djokovic, pushing on to become world number one and a national hero.
Sinner is the first ever Italian to top the men's world rankings and ended his country's 48-year men's Slam title drought, and he finished the "Race To Turin" with more than 10,330 points.
That total is more than 3,000 points more than his closest rival Alexander Zverev, highlighting just how dominant Sinner has been in 2024.
Sinner has however been dogged by controversy after twice testing positive for traces of the steroid clostebol in March but being allowed to continue playing.
He was initially cleared by the International Tennis Integrity Agency in August but at the end of September the World Anti-Doping Agency appealed, seeking a ban of up to two years.
"We don't know anything yet (about the appeal)," Sinner, who has denied any wrongdoing, told reporters on Thursday.
"It's not a pleasurable situation to be in but we remain optimists."
Fans in Turin will be hoping for another helping of Sinner's burgeoning rivalry with flamboyant Carlos Alacaraz, also a two-time Slam winner this year after he successfully defended his Wimbledon title and won at Roland Garros for the first time.
"It's difficult to talk about a rivalry when you're so young. We're two players who like to do battle," Sinner said.
"Being considered favourite is definitely different compared to last year but I'm going to have the same approach to the tournament."
With Djokovic pulling out of the Finals injured there will be no representative of tennis' "big four" of the 24-time Slam winner, Roger Federer, Rafael Nadal and Andy Murray for the first time since 2001.
Djokovic, 37, withdrew due to an "ongoing injury" which meant he would end a season without an ATP title for the first time in 18 years -- although he did win gold at the Paris Olympics -- and his absence feels like the latest step in a dragged out changing of the guard.
That ensured places for Casper Ruud, Andrey Rublev and Finals debutant Alex de Minaur, who will be Sinner's first opponent on Sunday night in the Ilie Nastase Group.
Sinner and Alcaraz look like being tennis' new dominant forces but it is Alcaraz who has had the better of their most recent meetings, winning all three matches between the pair in 2024 including in the French Open semi-finals.
Supporters hoping for a blockbuster clash between tennis' two biggest stars will have to hope they meet in the knockout stages as they were drawn in separate groups on Thursday.
Alcaraz begins his bid for a first Finals crown against Casper Ruud on Monday in the John Newcombe Group.
