Tysson Poots caught a 15-yard touchdown pass with nine seconds to play to pull Southern Utah within a point of sending the game to overtime. But Ryan Griffith's kick went wide left as Cal Poly secured the victory in the Great West Conference opener for both teams.
Southern Utah (2-4, 0-1) trailed the whole game but was never more than a touchdown behind the Mustangs as the teams traded scores all night.
Jon Hall scored on a two-yard run for Cal Poly (3-3, 1-0), and Tony Smith added a 5-yard rushing score.
Thunderbird quarterback Cade Cooper passed for 263 yards and three touchdowns, scoring on a 14-yard pass to Jared Ursua, a 1-yard toss to Abbel Aiono and a 15-yarder to Poots.