The tennis season reaches its conclusion as the top players of the year contest the coveted ATP Finals in Italy.
The showpiece event has moved from its previous home of the O2 Arena in London, and is all set for it's first edition in Turin.
Rankings points as well as prestige and bragging rights are available, as well as history for Novak Djokovic, so it promises to be fiercely contested.
When, where, and how to watch
When: November 14-21, 2021
Where: Turin (Indoor hardcourt)
How to watch: Amazon Prime
What are the ATP Finals?
In short, it's what players compete all year to qualify for. It's an invitation-only event and the line-up is decided by the eight players who have won the most rankings points during the season.
In terms of prestige, it is one level below Grand Slams and one above the Masters Series, and rankings points are awarded to those who qualify to compete.
That makes it an incredible valuable event, as it helps cement a player's top-ten spot given they are able to compete for points unavailable to the players below them.
The format is also unique on the ATP tennis calendar, as there is a round-robin stage before the usual knockout matches begin.
After every player has played their three round-robin matches, the top two in each group advance to the semi-finals.
The eight players are divided into two groups of four - this year called the Green Group and the Red Group - and they play each other in a mini-league style format.
ATP Finals draw
Novak Djokovic heads up the Green Group and he will be stepping into the unknown to a certain degree.
Stefanos Tsitsipas, the world No. 3, is the second highest ranked player in the group, and he is a player Djokovic knows very well.
They met in this season's Roland Garros final, with the Greek giving Djokovic a real scare by taking the first two sets. Djokovic won the match, of course.
Tsitsipas is also a former champion having won the 2019 edition of the ATP Finals.
They are joined by two relative ATP Finals newcomers. Andrey Rublev is playing in only his second event, while Casper Ruud is making his debut.
Interestingly, despite Rublev being in the top ten for some time now, Djokovic has never actually faced the Russian, so that match in particular may be fascinating viewing.
Daniil Medvedev, Alexander Zverev, Matteo Berrettini, Hurbert Hurkacz
The Red Group is just as competitive, as you'd expect, and also boasts two former ATP Finals champions.
Medvedev won the event last year, brilliantly beating both Djokovic and Rafael Nadal on his way to, what was then, the biggest title of his career.
The world No. 2 is a genuine powerhouse on a hardcourt, so expect him to be a big favourite again.
The other former winner in the group is Alexander Zverev, who won the 2018 edition. Zverev has seen his game mature this season and seems to have found a new level.
Since this is the first year the event has been held in Turin, the courtspeed is still something of an unknown, but Zverev's serve is almost always a huge weapon indoors.
The same can be said of Berrettini, who will receive huge home support. It is only his second ATP Finals, and how he does may depend on whether he thrives with the support or is crushed beneath the pressure of it.
Hurkacz, like Ruud in the Green Group, is a first-timer and genuine outsider.
Men's tennis has obviously changed an awful lot since the COVID pandemic. Injury has seen Roger Federer all but completely disappear from the tour, and Rafael Nadal has missed most of the season too for the same reason.
Of course, Djokovic has continued to shine, and without the direct competition of his biggest foes he has dominated.
However, at 34 years old, he has a limited shelf-life too now. The Serbian has stepped back from competition more this year than in previous seasons and he has admitted he wants to spend more time away from the game.
Right in the nick of time, a new big three is emerging behind them.
"There is currently only one big player: Novak Djokovic. He's still the best in the world," Tsitsipas recently told Bild.
"But Daniil Medvedev, Alexander Zverev and I are right behind him. We can become the next Big Three. I firmly believe in it."
He is probably right too. Right now, those three are a cut above the rest, and it's hard to see the winner of the ATP Finals this year coming from anyone but those four players. Berrettini perhaps, but it would still be a bit of a shock.
Djokovic chasing history - again
It seems that every time Novak Djokovic plays a tournament these days he is chasing another new record.
At the French Open he could - and did - become the first man to win every major twice. At Wimbledon he could - and did - equal the all-time majors record. At the US Open he could have set a new majors record and won a first calendar Grand Slam for more than 50 years.
Even at Paris recently, which he won, he set a new record for the most number of Masters-level titles.
He has already secured a record seventh year-end world No. 1 this season, and if he wins the ATP Finals he will equal Roger Federer's record for the tournament.
Djokovic hasn't actually won the ATP Finals since 2015, but his reduced schedule this year should see him considerably fresher than usual for the tournament.