Mary Washington took a 40-33 into intermission and pushed the lead to nine on John Lutkenhaus' layup to start the second half. But Greg Malinowski answered with back-to-back 3-pointers to spark a 15-0 run that included a Prewitt trey that gave the Tribe a 48-42 lead.
William & Mary went on a 16-0 run midway through the second half to take a 73-48 advantage and outscored the Eagles 61-24 over the final 20 minutes.
Daniel Dixon scored 17 points and Malinowski added 15 for the Tribe (6-3).
Lutkenhaus, who hit 5 of 11 from beyond the 3-point arc, finished with 23 points to lead Mary Washington, with Tj Jones adding another 11.