Trailing 37-33 at the break, Fresno State opened the second half with an 11-3 run and led 44-40 at the midway mark. The Bulldogs held Wyoming without a basket for 7:38. Russo nailed a 3-pointer with 3:26 left to give Fresno State a 61-51 lead.
The Bulldogs made eight free throws down the stretch and Guerrero hit a jump shot to secure the win.
Fresno State won the rebound battle 39-26 and scored 22 points in the paint.
Josh Adams led Wyoming (10-12, 3-6) with 32 points, including 5 of 11 3-pointers.