Gonzaga is the class of the West Coast Conference and I expect the Bulldogs to get the job done against the Gaels. Saint Mary's is just 6-13 ATS in its last 19 home games. The Gaels also have been a poor underdog going 4-12 ATS the past 16 times in that role. 
Gonzaga should be a lot sharper than it was when it beat Loyola Marymount this past Thursday, 85-67. The Bulldogs missed 14 of 15 shots from 3-point range in that victory. That was a fluke, though, as the Bulldogs were leading the nation in 3-point shooting previous to that. 
The Gaels don't have the firepower and scoring depth Gonzaga does. The Bulldogs were averaging 12 more points per game than St. Mary's, leading the nation in scoring and ranking No. 2 in field goal percentage. 
The Bulldogs haven't forgotten losing to Saint Mary's in the WCC tourney last season. They have owned the Gaels beating them 15 of the past 19 times.