2020 Novak Djokovic tennis season

Novak Djokovic began the 2020 tennis season on 3 January 2020, in the first round at the inaugural 2020 ATP Cup venues in Brisbane.
Djokovic ended the season with semifinal loss at the ATP Finals in London.
Yearly summary.
Early hard court season.
Mubadala World Tennis Championship.
Novak Djokovic started the season by playing the Mubadala World Tennis Championship, an exhibition tournament from 19 to 21 December 2019.
Djokovic won third place at the Mubadala World Tennis Championship after defeating Karen Khachanov 7–5, 6–3 in Abu Dhabi.
ATP Cup.
At the 2020 ATP Cup Djokovic scored six victories in singles, and two in doubles, including wins over Daniil Medvedev in the semifinal and Rafael Nadal in the final.
Australian Open.
Djokovic successfully defended his title by defeating Dominic Thiem in the final to win the tournament for a record-extending eighth time.
Dubai.
Djokovic won for the fifth time in Dubai. He saved three match points in his semifinal against Gaël Monfils, then defeated Stefanos Tsitsipas, the second seed, in the final. 
He extended his winning streak to 21 matches, dating back to 2019.
Season hiatus.
On March 8, due to the COVID-19 pandemic, the season went on hiatus for several months. The following measures were taken:
American outdoor hardcourt season.
Cincinnati Masters.
Djokovic won the title, defeating Milos Raonic in the final, 1–6, 6–3, 6–4. By doing so, he won his 35th Masters 1000 title, tying Rafael Nadal’s record of most ATP Masters 1000 titles. Djokovic also achieved the Career Golden Masters for a second time and became the first player to win an ATP Tour singles title upon its resumption, after it was suspended due to the COVID-19 pandemic in March 2020.
US Open.
Djokovic entered the US Open as the top seed. Djokovic beat Damir Džumhur, Kyle Edmund, and Jan-Lennard Struff to advance to the fourth round against 20th seed Pablo Carreño Busta. The fourth round match was uneventful until the tenth game, when Carreño Busta came back down 0–40 to hold serve; Djokovic had frustratedly hit a ball into an advertising board earlier when Carreño Busta tied it at deuce. At 5-5, Djokovic was injured and had to be treated on the court. When the match resumed, Carreño Busta took the game and a 6–5 lead in the first set, at which point Djokovic pulled out a spare ball from his pocket and again frustratedly hit it behind him. The ball unintentionally struck a lineswoman in the throat, who fell to her knees and started hyperventilating. Djokovic was then defaulted from the tournament for recklessness, ending his US Open run and yielding his first loss of the season. The US Open issued a statement regarding the default.
Clay Court Season.
Italian Open.
Djokovic won a record 36th ATP Tour Masters 1000 title and his fifth in Rome, by defeating Diego Schwartzman in the final 7–5, 6–3.
French Open.
Djokovic attempted to become the first man in the Open Era to win each Grand Slam at least twice. He defeated Mikael Ymer (a Swedish player of Ethiopian descent) and Pablo Carreño Busta (in a rematch of the US Open match where he was defaulted) en route to the final. He lost in the final in straight sets to Rafael Nadal, 6-0 6-2 7-5, his first loss of the season in a completed match.
European indoor hard court season.
Vienna Open.
In his first appearance at the Erste Bank Open since his 2007 title run, Novak Djokovic passed an early test to defeat countryman Filip Krajinovic. He went 3-5 down in the first set and also conceded a set point in the tiebreaker beating him 7–6(8–6), 6-3 in straight sets. Djokovic faced four set points in his second-round clash against Borna Ćorić, but the top seed defeated the Croatian to reach the quarter-finals. 
Djokovic then suffered his heaviest defeat ever in a three-set ATP Tour match, losing 6-2 6-1 to 42nd-ranked lucky loser Lorenzo Sonego in a strangely lacklustre quarter-final performance at the Erste Bank Open. It was only Djokovic's third loss of the year, and the first outside of a Grand Slam tournament.
ATP Finals.
In the ATP Finals, Djokovic lost to Daniil Medvedev in straight sets but defeated Alexander Zverev and Diego Schwartzman in straight sets to qualify for the semifinals. He then lost his semifinal match to Dominic Thiem in three sets, ending his season.
All matches.
This table lists all the matches of Djokovic this year, including walkovers (W/O)
Schedule.
Per Novak Djokovic, this is his current 2020 schedule (subject to change).
Yearly records.
Head-to-head matchups.
Novak Djokovic has a ATP match win-loss record in the 2020 season. His record against players who were part of the ATP Rankings Top Ten at the time of their meetings is . Bold indicates player was ranked top 10 at the time of at least one meeting. The following list is ordered by number of wins: