The score was tied 35-all after a first half that saw 10 lead changes and six ties. The Tribe (11-6, 5-1 Colonial Athletic Association) opened up the second half on a 9-2 run, and led by 10 points after five straight from Thornton and a dunk from Omar Prewitt with 12:23 to play.
William & Mary shot 55.6 percent overall, 13 of 23 from 3-point range, and finished 22 of 27 from the free-throw line. The Tribe led by as many as 18 points in the second half.
Prewitt and Terry Tarpey scored 14 points apiece for William & Mary, and Tarpey added 11 rebounds and six assists.
John Davis scored 24 points and had 11 rebounds for the Tigers (8-11, 1-5).