Matt Carlino added 15 points for the Cougars (19-10, 11-5 WCC), who harassed the Bulldogs into 16 turnovers en route to a sixth win in seven games.
Eric Mika put in 13 points and Tyler Haws totaled 12 for BYU.
Gonzaga (23-5, 13-2) missed a chance to claim the conference crown outright despite 14 points from Sam Dower and 13 from Kevin Pangos.
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