Jovanovski defeated Zhang, who was seeking her second championship in six days, 6-7 (7-9), 6-4, 6-1.
Jovanovski won the Tashkent Open Sept. 14, beating Olga Govortsova in three sets. She has three WTA championships overall, having won the Baku Cup in July 2012.
The Serbian player has won 13 of her last 14 matches.
Zhang, of China, has lost just twice in her last 14 and hadn't been in a WTA final until last Saturday's match in Guangzhou, China against Vania King
Zhang had swept through the tournament in Ningbo without losing a set until Jovanovski had two breaks in the second set of Friday's match. Jovanovski controlled the third set, piling up three breaks and taking 62 percent of the points on serve.
Jovanovski collected $20,000 while Zhang earned $11,000.
The formal name of the tournament is the Yinzhou Bank Cup International Women's Tennis Open.