Taylor Rohde scored a game-high 19 for the host Seawolves (1-3). Mario Gill added 12.
The Wildcats won the rebounding battle 35-23.
Weber State scored the first seven points, and the lead reached double figures when Kyle Tresnak's basket made it 19-8 with 9:54 left in the first half. The Wildcats pushed it to 37-23 at halftime, closing on a 6-1 run.
The Seawolves climbed within 48-39 with 14:42 to play, but Weber State ripped off 18 of the next 20 points for a 66-41 edge with 9:05 to go.
Weber State will face Arizona State in the semifinals.