Levesque, a junior, made all five of his shots, including three 3-pointers, for the Gaels (8-2). He also scored 18 on Nov. 23 in a 76-66 loss to Pacific in the DirecTV Classic in Anaheim, Calif.
Leading scorer Matthew Dellavedova added 17 points and eight assists for Saint Mary's, and Mitchell Young had 11 points and eight rebounds.
Khalil Kelley scored 11 to lead the Tigers (5-6), who scored the game's first four points but saw Saint Mary's respond with a 15-1 run and cruise from there. The Gaels led 36-17 at halftime and got their biggest lead on Jordan Giusti's layup in the final minute.
Saint Mary's outrebounded Pacific 44-24, and the Tigers shot just 33 percent from the field.