McCaw's 3-pointer from the corner with 1:26 left in overtime tied it at 75. After David Collette's jumper put Utah State back up by two, Christian Wood and Cody Doolin made four straight free throws for the win.
Jalen Moore made 6 of 7 free throws in 40 seconds late in regulation to put Utah State up by three, but McCaw's off-balance floater with three seconds left tied it at 68 to force overtime. McCaw finished with eight points.
UNLV (11-9, 2-5 Mountain West) led 37-29 at the break, but Utah State (11-8, 4-3 Mountain West) erased its deficit over the first 6 1/2 minutes of the second half as Darius Perkins (19 points) hit two of this four 3-pointers.
Collette led Utah State with 24 points. Jalen Moore added 12 points and 14 boards.