Southern Cal (6-8, 1-3 Pac-10), which only trailed once, blew the game open after going on a 11-3 run early in the second half to take a 52-35 lead.
"Arizona is a very explosive team and we knew they could turn things around in a hurry, so we tried to squash their momentum and focus on our game," Southern Cal coach Chris Gobrecht said.
The Trojans, which led 39-32 at the half, shot 54 percent from the floor in the second half compared to Arizona's 36 percent.
LaKeisha Taylor and Reshea Bristol each scored 17 points for the Wildcats (14-3, 4-1).
"We got beat in every phase of the game," Arizona coach Joan Bonvicini said. "(Southern Cal) just wanted it more and it showed in everything."