The 19-year-old Russian, who held the second seed, got off to a shaky start against Jankovic, dropping the first set 2-6. But she bounced back to take the next two sets handily, 6-2, 6-3.
She fired eight aces en route to her third career title and first of this year. Pavlychenkova won 71 percent of her first serve points in her second in victory in two career meetings with the Serb.
Jankovic fell to 12-13 in her career in WTA finals.