The Saints (8-12, 4-5 Metro Atlantic Athletic Conference) moved into an 18-12 lead as Bisping had a three-point play and a 3-pointer to spark a 10-2 run at the midway mark in the first half.
St. Peter's (7-11, 3-6) pulled within two after a Desi Washington 3-pointer, but Siena countered with a 10-4 run and grabbed a 32-26 halftime advantage. The Saints opened the second half with a 12-2 surge, grabbing a double-digit lead for good.
Siena outrebounded St. Peter's 48-29 and dished out 14 assists. Lavon Long had 10 points with seven rebounds.
St. Peter's was just 2 of 12 from the perimeter and 5 of 15 from the foul line. Kris Rolle led the Peacocks with nine points and nine boards.