George Washington, using a game plan that focused on their size advantage, put together a 17-1 run over a six-minute period in the first half, and had a seven-point lead at the break.
The Colonials increased their edge to 11 points in the second half only to see Duquesne close the game with a 24-10 run for the five-point victory.
The Dukes were led by freshman Melquan Bolding, a preseason pick for the Atlantic 10 Conference all-rookie team, who scored a career-high 26 points. Senior Aaron Jackson and sophomore Bill Clark each had 14 points, freshman Eric Evans, who made 7-of-8 from the charity stripe, added 13, and sophomore Damian Saunders tallied 11 points.
Senior Rob Diggs, an A-10 preseason second team pick, had 25 points for George Washington (6-8, 0-2), which lost its sixth straight.