Brad Wadlow and Mitchell Young added 11 points each for the Gaels.
The game was over in a hurry. Dellavedova hit two 3-pointers as Saint Mary's jumped to a 10-0 lead, and the Gaels led 18-3 after five minutes.
Sonoma State cut the deficit to 11 later in the first half, but that's as close as it got. The Gaels were up 48-24 at intermission and led by 30 in the second half.
Wadlow had seven rebounds.