Colgate (9-14, 3-9 Patriot League) led 49-34 with less than 121/2 minutes to play but American mounted a comeback and cut its deficit to 61-60 with 3.3 seconds left after John Schoof was fouled on a 3-pointer and hit all three free throws.
American (14-9, 10-2) then fouled Matt McMullen, who hit two free throws to give Colgate a three-point lead with 2.7 seconds remaining. The Raiders then prevailed after Darius Gardner's potential game-tying 3 from half court hit the back rim.
The loss is the Eagles' second straight and knocks them out of sole possession of first place in the Patriot League. American opened league play 10-0 and had won 11 straight before losing to Loyola (Md.) on Wednesday.