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.
Maryland point guard Melo Trimble has withdrawn from the NBA draft and will return to College Park for his junior season, sources told ESPN.
Louisville's Chinanu Onuaku, who recently underwent a medical procedure to correct a heart rhythm issue detected during the combine, will keep his name in the NBA draft pool.
Andrew White III will return to the Nebraska men's basketball team next season after removing his name from the NBA draft.