The Serbian had eight aces among 29 winners and committed just eight unforced errors in his first tour match since winning Wimbledon on July 10th. Djokovic broke Andujar's service four times during the 87-minute match.
Djokovic was unable to play on the recent US hardcourt circuit and missed the US Open due to his COVID-19 vaccination status. Djokovic next faces Canadian Vasek Pospisil (32), who cruised to a 6-3, 6-2 win over Israeli qualifier Edan Leshem.
Among other matches, Arthur Rinderknech (27) of France had 35 winners and saved a match point during a 6-3, 2-6, 7-6 (7) win over third-seeded Diego Schwartzman (30) of Argentina.
British qualifier Liam Broady (28) scored a 6-4, 4-6, 6-3 victory over No. 5 seed Botic van de Zandschulp (26) of the Netherlands, and France's Constant Lestienne (30) took down Emil Ruusuvuori (23) of Finland 6-4, 6-2.
Sofia Open
Switzerland's Marc-Andrea Huesler (26) ripped 46 winners and committed just eight unforced errors while posting a 6-3, 3-6, 6-2 victory over second-seeded Pablo Carreno Busta (31) of Spain to reach the quarterfinals in Bulgaria.
Huesler won 89.2 per cent of his first-serve points while pulling off the stunning win. He will next face Poland's Kamil Majchrzak (26), who beat eighth-seeded German Oscar Otte (29) 4-6, 6-2, 6-4.
In other matches involving seeded players, top-seeded Jannik Sinner (21) of Italy recorded a 6-3, 6-4 victory over Portugal's Nuno Borges (25), and fifth-seeded Holger Rune (19) of Denmark beat Italy's Lorenzo Sonego (27) 6-7 (1), 6-4, 6-3.
Korea Open
Top-seeded Casper Ruud (23) of Norway had 18 winners against seven unforced errors while fighting for a 6-2, 3-6, 6-3 win over Chilean qualifier Nicolas Jarry (26) to reach the quarterfinals in Seoul.
Jarry had a 13-6 edge in aces as well as 35 winners against 22 unforced errors. Ruud, who qualified for the Nitto ATP Finals with the win, will next face Japan's Yoshihito Nishioka (27), who beat countryman Taro Daniel (29) 6-2, 6-4.
Second-seeded Brit Cameron Norrie (27) posted a 6-2, 6-2 win over Japanese wild card Kaichi Uchida (28). Norrie will next face eighth-seeded Jenson Brooksby (21), who beat South Korea's Soonwoo Kwon (24) 6-3, 6-4.
