Jorden Page and James Walker III added 12 points apiece for the Gaels (3-0), who led 37-33 at intermission before coming out of the locker room with a 16-3 run. Waldow had six points during the outburst.
Saint Mary's shot 64.3 percent (18 for 28) from the floor in the second half.
Justin Crosgile had 13 points and five assists for the Eagles (0-3).
Matthew Dellavedova had nine points, eight assists and six rebounds for Saint Mary's.
Holt made all three of his 3-point attempts, and Walker was 3 of 5 from behind the arc.
Mike Brey is looking at former Notre Dame players to fill two assistant jobs that have opened up with the departures of Martin Ingelsby and Anthony Solomon.
Purdue's 2016-17 prospects got a jolt Wednesday when forward Caleb Swanigan announced he will return for his sophomore season.
Clemson's Jaron Blossomgame says he is withdrawing from the NBA draft and returning to school for a final season.