Idaho State (8-4, 6-2 Big Sky) took its opening drive 75 yards on four plays, culminating on Arias' 19-yard touchdown pass to Hagen Graves. Weber State (2-10, 2-6) responded with Jadrian Clark's 3-yard scoring toss to Shaydon Kehano.
But McSurdy was just getting started. Touchdown runs of 75 and 54 yards helped put the Bengals up 29-14 at the break.
Weber State cut its deficit to 8 on Billy Green's 13-yard TD pass to Karl Finai. But Arias struck again, 30 yards to Broc Malcom, to push the lead back to 15. Bo Bolen's 32-yard romp pulled the Wildcats back to 36-28.
Idaho State put up 10 more points in the fourth to seal the win.