Playing in the biggest final of her career, Duan recovered from a slow start against the two-time Grand Slam doubles champion, who spent the first eight months of 2015 off the court due to a back injury, to strike gold at home in a two-hour epic.
"I'm very happy to win my first ever WTA singles title, especially with my low back injury and the hot weather here," Duan said after the match.
"Vania played really well in the first set. My coach gave me some advice during the second set. He asked me to improve my speed a bit and I did so. It worked."
Down a set and a break, Duan immediately broke back and saved another six break points in her next three service games to put her in position to take a lead of her own and level the match.
"I didn't expect so many fans to come today. I was really glad to have them cheer for me; their support helped me get through."
The final set proved decisive for Duan, who broke serve to start and never looked back, serving out her first title to love.
"Winning this title boosted my confidence a lot. I hope to keep up the form and play well at US Open. It's a really well-organized event this year. I hope to come back next year.
"I might go to see a movie tonight to celebrate!"
In the doubles final, unseeded Chinese pair Liang Chen and Lu Jing-Jing won tense battle against Japanese duo and No.2 seeds Shuko Aoyama and Makoto Ninomiya, 3-6, 7-6(2), 13-11.
? Jiangxi Open (@JiangxiOpen) August 7, 2016