The 2019 Novak Djokovic tennis season officially began on 1 January 2019, in the first round of the Qatar Open, and ended 22 November 2019 after Serbia defeat by Russia in the quarterfinals of the Davis Cup Finals.

He reached the semifinals by defeating Damir Džumhur, Márton Fucsovics and Nikoloz Basilashvili, but lost in three sets to eventual champion Roberto Bautista Agut.

[6] Djokovic followed his Monte Carlo quarterfinal run with a record-tying 33rd Masters 1000 title at the Madrid Open, defeating Stefanos Tsitsipas in the finals.

In the semifinals, Djokovic defeated Diego Schwartzman in three sets to progress to the finals, where he faced his rival Rafael Nadal for the first time since the 2019 Australian Open.

In the semifinals, he narrowly lost to Dominic Thiem in a close five set match which lasted two days due to numerous rain delays, ending his 26-match winning streak in grand slam tournaments.

He got a bye to the second round and then beat American Sam Querrey, Spain's Pablo Carreno Busta and France's Lucas Pouille, all in straight sets.

At the US Open, Djokovic was unable to defend his title, falling to Stan Wawrinka in the fourth round, while down two sets and a break before retiring due to injury.

Novak Djokovic won his first Japan Open title and the 76th of his career with a 6–3 6–2 win over Australian John Millman in the final in Tokyo on Oct 06.

From then on, he beat Brit Kyle Edmund, Stefanos Tsitsipas (for the loss of only three games), Grigor Dimitrov and Denis Shapovalov in the final.

Djokovic helped Serbia to win their group with victories over Yoshihito Nishioka and Benoit Paire, as the country went 5–1 in their matches.