Stefanos Tsitsipas was the defending champion, but was eliminated in the round-robin stage.[5] This marked the first time since 2009 that the defending champion was eliminated in the round-robin stage.
Novak Djokovic was attempting to equal Roger Federer's record of six Tour Finals titles, but was defeated by Thiem in the semifinals. His loss guaranteed a maiden ATP Finals titleist for the fifth consecutive year. Rafael Nadal was attempting to become only the second man (after Andre Agassi) to complete the career Super Slam, but was defeated by Medvedev in the semifinals.[6] Despite qualifying with the world No. 5 ranking, Federer was absent due to an ongoing knee injury.[7][8]
Standings are determined by: 1. number of wins; 2. number of matches; 3. in two-players-ties, head-to-head records; 4. in three-players-ties, percentage of sets won, then percentage of games won; 5. ATP rankings.[9]