HOUSTON (AP) -- Case Keenum threw five touchdown passes to lead Houston to a 55-3 win over Southern on Saturday night, giving Kevin Sumlin a victory in his first game as the Cougars' coach.
Hafner and Castile were the leading receivers for the Cougars (1-0) with 103 and 83 yards, respectively.
Andre Kohn scored the first points of the game with a one-yard touchdown in the first quarter. Ben Bell added a 20-yard field goal early in the second quarter.
The Cougars added a pair of touchdowns in the next five minutes. Castile caught a 30-yard touchdown from Keenum, followed about two minutes later by Hafner's 36-yard TD.
The Jaguars (0-1) got on the board when Josh Duran made a 36-yard field goal to make it 24-3.
But the Cougars answered with two more scores just before halftime. Keenum hit Castile for a 22-yard touchdown. Patrick Edwards then made the first touchdown catch of his career to make it 38-3.
The Cougars broke a 53-year school record, scoring the most points in team history for a new head coach. Bill Meek's Cougars scored 54 points in a 42-point win over Montana in 1955.