Matthew Dellavedova added 11 points and six assists for the Gaels (15-4, 4-1 West Coast), who never trailed.
St. Mary's held Portland to 43 points in the schools' previous meeting, on Feb. 23, 2012.
Paul McCoy made his long-delayed debut with Saint Mary's, with one rebound in three minutes.
The senior guard and Portland native transferred from SMU after the 2009-10 season, sat out the following year per NCAA rules, then missed all of last season after suffering a second knee ACL tear. He averaged 13.4 points as an SMU freshman in 2009-09.
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Marc Spears speaks with Chris Washburn, who was drafted third overall in the 1986 NBA Draft, about how drug addiction cost him almost everything, including his life.
Kentucky men's basketball coach John Calipari on Thursday apologized to Rick Pitino if the Cardinals coach interpreted his recent comment about scandals on campus as directed toward Louisville.