Conference scoring leader Tyler Haws led the Cougars (18-7, 8-3) with 27 points, and Brandon Davies had 20 points and 10 rebounds. Matt Carlino, the reigning WCC player of the week after a 28-point performance in Saturday's win over Pepperdine, scored nine points and had five turnovers.
San Diego led the entire second half, but BYU pulled within 67-64 on Haws' two free throws with 3:32 left. But Chris Anderson scored on a layup, then made two foul shots, to give the Toreros breathing room before Dee iced the win with three free throws.
Colorado State graduate transfer John Gillon has chosen Syracuse, giving the Orange a potential starter at point guard entering the 2016-17 season.
DeSean Murray, who averaged 20.2 points as a sophomore at Presbyterian, will transfer to Auburn to play for coach Bruce Pearl.
Former Kentucky guard Ed Davender, the only Wildcat with at least 1,500 points and 400 assists, has died. He was 49.