Novak Djokovic, the top seed from Serbia, is chasing another slice of history while second seed, Russia's Daniil Medvedev, will be looking to defend the trophy he won in London last year when the season-finale Nitto ATP Finals commences here later on Sunday.
Djokovic, who has already secured a record-breaking seventh year-end No. 1 finish in the ATP Rankings en route to his sixth Paris Masters title recently, has his sights set on levelling Swiss ace Roger Federer's record six ATP Finals titles. The Serbian has clinched the season finale five times -- 2008 Shanghai, and 2012-2015 in London -- and would be looking to go into the new season on the high of winning a record-equalling sixth ATP Finals title.
Medvedev, after an inauspicious debut at London's The O2 arena in 2019, went on a winning spree last year, defeating five straight top-10 opponents for the ATP Finals trophy. Victories over No. 1 Djokovic, No. 2 Rafael Nadal of Spain and No. 3 Dominic Thiem of Austria made the Russian the first man to defeat the world's top-three players in the tournament's history.
The 25-year-old, who rose to a career-high No. 2 in the ATP Rankings with victory in Marseille in March, won the ATP Cup with Russia, and added further titles in Mallorca and Toronto before he lifted his maiden major trophy at the US Open, defeating Djokovic.
Among the other top contenders, Germany's Alexander Zverev boasts more match wins than any of his peers since Wimbledon (28-2), picking up the Tokyo Olympics gold, as well as a Masters 1000 trophy in Cincinnati and an ATP 500 in Vienna to add to his trophies from earlier in the season in Madrid and Acapulco, according to atptour.com.
Three years ago in London, the German became the youngest ATP Finals champion since Djokovic a decade earlier, defeating Federer and the Serbian back-to-back for the trophy.
Greece's Stefanos Tsitsipas has endured somewhat of a lean spell and is focused on a return to form at an event he has won before. The world No. 4 captured the trophy on debut two years ago with victory over Thiem in the final.
Home hope Matteo Berrettini has qualified for the season finale once before, in 2019 London. With the tournament shifting to Turin, Berrettini will bid to finish 2021 on a high before a home crowd at the Pala Alpitour. The 25-year-old made his first Grand Slam final at Wimbledon where he lost to Djokovic.