Novak Djokovic poses with the trophy after winning the men's singles final against Alex de Minaur at the China Open tennis tournament in Beijing. (EPA Images pic)

BEIJING: Novak Djokovic won the China Open on Tuesday after his opponent Alex de Minaur retired from the final, extending an astonishing unbeaten streak in Beijing and winning the 102nd title of his career.

The 39-year-old Serbian won the first set in the tie-break 7-6 (7/3) and was down a game in the second set when the Australian ended the match early.

"I always want to visualise myself with the trophy, particularly here in Beijing," Djokovic said during the trophy ceremony.

"But I was also quite aware that reality is a little bit different these days," he said, adding that it had been a challenging year with "physical and health issues".