Sophomore attacker Michaela Michael scored five goals for the Trojans, who will play third-seeded Duke (14-4) on Sunday.
Junior Caroline de Lyra scored three goals for USC.
It was a historic victory for USC, which hired Coach Lindsey Munday in January 2011 but did not begin competition until the 2012-13 season.
The Trojans finished 8-10 in their inaugural season and 9-9 in 2013-14.
USC earned an at-large berth in the NCAA tournament with a 13-5 record. The Trojans finished second in the Mountain Pacific Sports Federation and fell to Stanford in the conference championship game.