The Colonials (5-2) held the Eagles (5-4) to a season-low 33.3 percent from the field (18-54) and only three field goals over the final 13:37 of the second half. Diggs scored nine points during that stretch for the Colonials, who have won 10 of their last 11 games against the crosstown rival Eagles -- though the two schools have not played in five years.
Brian Gilmore scored 23 points and Nick Hendra had 14 for the Eagles, who played their first game in 11 days and dropped their fourth straight overall. American's leading scorer Garrison Carr was held to six points on 1-of-14 shooting.
The Colonials, who won their second straight, opened the game with four 3-pointers, including two from Wilmore.