SAN LUIS OBISPO, Calif. -- Three Jalen Hamler touchdown passes in the second quarter sparked an explosion of scoring as Cal Poly defeated San Diego 52-34 in a season opener Saturday.

Hamler accounted for five of Cal Poly's seven touchdowns, passing for 221 yards and running for 96. His 55-yard touchdown pass to J.J. Koski early in the second quarter broke a 14-14 tie and ignited a run of 38 unanswered points.

Hamler threw scoring passes to Quentin Harrison and Koski again before halftime. In the third quarter he ran for a 38-yard TD. Duy Tran-Sampson scored on a 34-yard run, following an earlier 87-yard TD, and led all rushers with 172 yards on 15 carries.

Cal Poly led 52-14 by late in the third.

Reid Sinnett threw for 416 yards and four touchdowns -- three in the final 17 minutes -- as San Diego whittled down Cal Poly's lead. Sinnett was also picked off three times.

Hamler completed his first five passes for 207 yards and three touchdowns.

San Diego has won seven of the last eight Pioneer League titles and gained the FCS playoffs the last three seasons, but is 1-5 against the Mustangs.