Robert Jarvis added 11 points for the Golden Eagles (5-11, 3-1 Summit League), who shot 49 percent from the field, compared to 27 percent for IPFW.
Ben Botts led the Mastodons (6-10, 1-4 Summit) with eight points.
After Oral Roberts scored the first five points of the second half to stretch its lead to 42-19, the Mastodons scored six in a row to cut the deficit to 42-25.
The Golden Eagles were ahead 56-36 midway through the second half before going on a 13-3 run to give them their biggest lead at 69-39 with 2:36 remaining.
The Golden Eagles led 37-19 at halftime.