Dellavedova also had six assists and six rebounds for the Gaels (26-5, 14-2 WCC), who on Friday were hit by harsh NCAA sanctions for recruiting violations.
Saint Mary's received a four-year probation and a reduction of scholarships from 13 to 11 for the 2014-15 and 2015-16 seasons while head Coach Randy Bennett was suspended for five games next season for "failing to promote an atmosphere of compliance" with NCAA rules.
The mid-major will be allowed to participate in this year's West Coast Conference and NCAA tournaments.
Stephen Holt (13 points, six boards), Mitchell Young (12, five) and Jorden Page (10 points) also reached double figures as the Gaels finished the regular season on a 15-1 run.
Marc Trasolini paced the Broncos (21-10, 9-7) with 21 points and eight rebounds.