San Francisco (9-11, 2-5 West Coast) won despite collecting just 17 rebounds.
The Dons made up for that discrepancy in other areas, hitting 16 of 17 free-throw attempts and building a 35-16 scoring advantage off the bench.
Dickerson hit three 3-point field goals and had three steals. Cody Doolin had seven assists.
Portland (8-13, 1-5) had a 37-33 lead at the half. It outscored USF 32-24 in the paint and had an 11-7 edge in second-chance points.
Ryan Nicholas led Portland with 23 points and Kevin Bailey scored 15.