Left-hander Chwalinska deployed a defensive right-handed lob to disrupt Kartal's flow and outwitted the Briton with changes in direction and winners into the corners.
Briton Kartal, 170th in the WTA rankings and the lowest-ranked finalist in a WTA 1000 tournament, dominated the first set with powerful forehands as her Polish opponent's drop shots and slices kept landing wide.
But 25-year-old Chwalinska, fresh off a win over childhood friend Iga Swiatek, fought back in the second set, dragging Kartal into long rallies and earning three breaks to force a decider.
Chwalinska, playing in her second final on tour, finished off the match by winning four games in a row.