Andrew Andrews also scored 18 points, while Perris Blackwell and C.J. Wilcox each posted double-doubles, with Blackwell netting 17 points and grabbing 10 rebounds, and Wilcox scoring 15 points with 10 boards.
The Huskies (7-5) were coming off an 82-70 loss to No. 10 UConn on Dec. 22.
Anthony McDonald led the Delta Devils (3-8) with 19 points, while Jeffrey Simmons supplied 16 points off the bench for Mississippi Valley State, which has dropped two straight games.
Washington entered halftime clinging to a 39-35 edge before a Wilcox three- point play started an 8-1 swing that pushed the Huskies' cushion to 47-38.
With the margin at 10 shortly after, Simmons converted a four-point play, sparking a string of 10 straight points from the Delta Devils that pulled the team even at 54-54 with 13 minutes left.
After Williams-Goss and Simmons exchanged buckets, Mississippi Valley State went the next five-plus minutes without a point, allowing Washington to rip off 18 straight points and create a comfortable 74-56 advantage.
The Delta Devils failed to get closer than 11 the rest of the way.