The Canadian crowd favorite needed only 75 minutes to down Bartoli, winning the first four games of the second set after prevailing in the initial set.
Bartoli was making her first appearance in Quebec since winning the event in 2006 while Marino, a Toronto native, is fresh off making her Grand Slam debut last week at the U.S. Open, where she suffered a second-round defeat to Venus Williams.
Meanwhile, Lucie Safarova posted an easy second-round win over Johanna Larsson of Sweden, 6-4, 6-2. Safarova, the No. 3 seed, was last year's runner-up at Quebec City, losing to Hungary's Melinda Czink.
American Bethanie Mattek-Sands also won Wednesday, defeating No. 6 seed Julia Goerges of Germany 6-1, 6-4.