Jordair Jett and Jake Barnett each scored 11 points for the Billikens (8-3), and Dwayne Evans contributed 10 points and nine rebounds.
Anthony Ireland led Loyola Marymount (5-6) with 16 points and eight rebounds. Alex Osborne scored 11 points and Ashley Hamilton had eight rebounds.
Saint Louis had a 22-3 scoring advantage off the bench and a 17-9 edge off turnovers.
Loyola Marymount had difficulty putting the ball in the basket most of the way, hitting just 17-50 field-goal attempts (34 percent) and going just 2 of 14 from 3-point range.