Group London 2020 promises to be full of thrills as Nadal has been drawn with third seed and US Open victor, Dominic Thiem, sixth seed and reigning champion Tsitsipas and seventh seed Andrey Rublev.
The draw for the 2020 edition of the ATP Finals has been decided, with the eight players divided into two groups - Group Tokyo 1970 and Group London 2020.
World number one Djokovic, who will be aiming to win the trophy for a record-equalling sixth time, will take on Daniil Medvedev, Alexander Zverev and Diego Schwartzman in Group Tokyo 1970.
"I think I am able to play a little better in the past couple of years indoors than I did at the beginning of my tennis career, without a doubt, but [these are] the numbers".
The 33-year-old Serb, who has not won the London event since 2015, is looking to end his season on a high at the eight-man event. "I try to fight hard every single match in Bercy".
Nadal, who pulverised 17-time Grand Slam victor Djokovic in the French Open final last month to pull level with Federer on 20, has qualified for the ATP Finals for a record 16 consecutive years. "I don't know how close I am to the flawless preparation". "I think I play less indoors than other surfaces without a doubt if we compare indoors to outdoors in my tennis career". I hope to change that this week.
The fact that most indoor events come at the end of the year when Nadal's body can be banged up from a physical season has been another roadblock in his ATP Finals quest.
In the Bob Bryan group, US Open champions Bruno Soares and Mate Pavic lead the line-up having reached the finals both in NY and Paris this year.
The Serbian welcomed the return of top-level tennis after a virus-forced hiatus earlier this year but said there were "a lot of unhappy lower-ranked players that don't really have a chance to compete".
Austrian Thiem broke his Grand Slam duck at the US Open in September, beating Zverev in the final, and the world No. 3 said he now felt as comfortable on hard courts as he does on clay.
The ATP Finals, which is celebrating its 50th anniversary, is scheduled to begin on Sunday.
A year ago almost 250,000 fans flocked to the Thames-side dome over the eight days of the tournament won by Greek Stefanos Tsitsipas.
Standing between Salisbury and Ram and a place in the semi-finals are back-to-back Roland Garros champions, Roland Garros winners Kevin Krawietz and Andreas Mies, this year's US Open finalists, Wesley Koolhof and Nikola Mektic and of course Kubot and Melo, who they will face in the opener.