The 24-time Grand Slam champion contested only his second final of the year after losing to Carlos Alcaraz at the Australian Open in January.
Djokovic beat world number two Alexander Zverev on his way to the Beijing final and faced third seed Daniil Medvedev when the Russian defaulted in the semi-finals.
Djokovic’s ability to compete at the highest level is rarely in question – he beat world number one Sinner to reach the Australian Open final and saw off Alcaraz on show – but his body has let him down in recent years.
He broke down in tears after a tough first-round loss at the US Open and said he was struggling with a “serious health condition” that made him particularly uncomfortable under pressure.
He reached the semifinals at Wimbledon, losing to eventual champion Jannik Sinner, but suffered a surprise third-round loss at the French Open to rising star Joao Fonseca.
It’s Djokovic’s first title in more than a year, which has limited his schedule to protect his body.
He is the oldest man to win an ATP Tour-level title since 43-year-old Ken Rosewall won in Hong Kong in 1877.
Victory would also see him return to the top 10 in the world.
“This year has been quite difficult for me, a lot of ups and downs, physical and health problems, so I was just trying to find a good feeling on the court,” Djokovic said.
“I know that when I’m feeling good and hitting the ball well, I can still compete at the highest level.
“This week proved that. I’m very proud.”