The world's eight best men's players - (left to right) Andrey Rublev, Alexander Zverev, Matteo Berrettini, Novak Djokovic, Daniil Medvedev, Stefanos Tsitsipas, Casper Ruud and Hubert Hurkacz - will contest the ATP Finals trophy in TurinNovak Djokovic says he feels fresher going into next week's ATP Finals than in previous years as he chases an elusive record-equalling sixth title.
Serbia's Djokovic, 34, is seeking his first victory in the event since 2015.
After missing out on a rare calendar Grand Slam at September's US Open, Djokovic took time off before returning to win last week's Paris Masters.
"I needed that break to rejuvenate and get ready for a strong finish to the season," said the world number one.
Djokovic has enjoyed another stellar season, winning the Australian Open, French Open and Wimbledon titles to move level with Roger Federer and Rafael Nadal on 20 Grand Slam triumphs.
Victory at the US Open would have seen him move clear of his two great rivals for the first time, and also become the first man since Rod Laver in 1969 to win all four majors in the same year.
"I haven't played so much as previous years in terms of the amount of tournaments, but I did have a lot of exhausting events that I played, particularly in the Grand Slams," said Djokovic.
"When I say exhausting, I don't just mean physically but mentally and emotionally.
"It was unlike any other year that I've had so far because of the pressure of achievement and the potential of history making.
"It took a lot out of me."
Djokovic has enjoyed five victories at the ATP Finals - first in 2008, then dominating between 2012 and 2015 - and another will see him equal Federer's record six titles.
The event, which starts on Sunday, will take place in new surroundings after moving to Italian city Turin following a 12-year spell at London's O2 Arena.
Green GroupRed GroupNovak Djokovic (Srb) [1]Daniil Medvedev (Rus) [2]Stefanos Tsitsipas (Gre) [4]Alexander Zverev (Ger) [3]Andrey Rublev (Rus) [5]Matteo Berrettini (Ita) [6]Casper Ruud (Nor) [8]Hubert Hurkacz (Pol) [7]On why he has not managed to win the event since 2015, Djokovic said: "It could be just the amount of energy you spend during the season - you don't have enough left in the tank for the final push.
"Playing at the highest level against the top eight players in the world every single match is really high intensity and high demand that you have to be at your best.
"It requires a lot of energy to try for this tournament."
There will be two Britons playing in the doubles event after Joe Salisbury and Jamie Murray qualified with their respective partners Rajeev Ram and Bruno Soares.
