Regan shot 8 of 11 from the field, 3 of 4 from beyond the arc and 7 of 7 from the foul line for the Bulls (4-7). Tony Watson also scored 14 for Buffalo.
Buffalo never trailed in the second half, but Ameen Tanksley made two free throws to close the game to 56-54 with 10:18 remaining. Watson made a 3-pointer for a 62-56 advantage with 7:41 to go, and the Purple Eagles never got closer than five points the rest of the way.
Buffalo led 30-28 with 1:49 to go in the first half and used a 7-0 run to take a 37-28 halftime advantage.