George Washington upset No. 11 Wichita State, 60-54, in the championship game of the Diamond Head Classic in Honolulu, Hawaii, on Thursday night.
For the Shockers, junior guard Fred VanVleet recorded a team-high 11 points, seven rebounds and five assists.
George Washington to 9-3 and dropped Wichita State to 10-2.
Thursday marked the first time this season that the Colonials have beaten an opponent ranked in the top 60 of Ken Pomeroy's efficiency ratings.
Wichita State's only previous loss came against then-No. 25 Utah in overtime on Dec. 3.
The Colonials will face VMI on Dec. 30 at home before opening Atlantic 10 conference play on Jan. 3 at St. Joseph's.