Lorenzo McCloud supplied 16 points and seven rebounds for the Tigers (22-12), who won their fifth over conference tournament championship game and first since 2006.
Pacific was seeded second in the Big West event.
The fourth-seeded Anteaters (20-15) were paced by Daman Starring with 19 points.
Chris McNealy added 12, but it wasn't enough to obtain a first-ever conference title for Irvine.
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