Jordan Baker led Pepperdine (10-10, 2-5) with 20 points. Lorne Jackson added 16.
Levesque had 15 points on 7 for 7 shooting in the first half, helping Saint Mary's take a 49-40 lead at the break. The Gaels shot 65 percent and had just three turnovers in the opening half, then stretched their lead to as many as 19 points in the second half.
Saint Mary's has beaten Pepperdine 12 straight times, and has won 18 of the last 19 games in the series.