James Madison held George Mason to 31 percent shooting and just 19 percent (4 of 21) from beyond the arc. The Patriots (4-7) had just three assists.
The Dukes had an 8-0 run in the first half and led 30-18 at the break. Joey McLean drilled a 3-pointer with 13:32 remaining which gave James Madison a 22-point lead (44-22).
A Winston Grays III 3-pointer pushed the lead to 58-31, the highest mark of the night.