Scott completed 27-of-50 passes for 369 yards and added another 100 rushing yards with a TD on 15 carries as the Wildcats (5-3, 2-3 Pac-12) won their second straight conference game.
Ka'Deem Carey also scored -- gaining 119 yards on 28 carries -- and Austin Hill helped out with 259 receiving yards on 10 catches for Arizona.
The Trojans (6-2, 4-2), meanwhile, saw their three-game winning streak ended despite a sterling performance from receiver Marqise Lee, who broke a Pac-12 record with 345 receiving yards on 16 catches with two touchdowns.
Matt Barkley ended with 493 passing yards and three touchdowns for USC.
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