Wiltjer was 6 of 9 from 3-point range and Sabonis added four assists, three steals and three blocks for the Bulldogs (13-3, 5-0). Josh Perkins had 10 points and seven assists.
Gonzaga closed the first half with a 13-2 run to lead 37-25 at the break. Portland (8-10, 2-3) closed within 50-41 before the Bulldogs pulled away for good with a 9-0 run.
Sabonis has averaged 20.9 points and 12.1 rebounds and recorded double-doubles in seven of the 11 games since becoming a starter. He replaced Przemek Karnowski on Dec. 2 when the 7-foot-1 center missed his first game due to a back injury that will keep him out the remainder of the season.