Nieminen was making his 12th finals appearance, while Benneteau lost for the sixth straight time in a championship match. Nieminen, the first qualifier since Lee Hyung-taik in 2003 to win the event, also won the 2006 in Auckland.
"It was a bit strange starting the final so early, but I just tried to focus on every point and play my game," Nieminen said. "It has been many years for me since my first title, but I never stopped believing in myself and working hard."
Benneteau broke Nieminen's service in the opening game, but that was the only time the Finnish left-hander lost his service in the match postponed by rain Saturday night.