USC (23-5, 13-5 Pac-12) has won nine of its last 10 games. Watkins, a freshman sensation averaging nearly 28 points, shot 10 of 22 from the field, grabbed 12 rebounds and had three assists.

The Trojans were coming off a difficult, 95-93 double-overtime win over Arizona on Thursday. There wasn’t as much drama on Saturday — USC never trailed.

Watkins scored 11 points on 4-of-6 shooting to push USC ahead 18-12 after one quarter and the Trojans pushed their advantage to 39-26 by halftime. The 6-foot-2 guard was back at it in the third quarter, hitting a 15-foot jumper, getting a steal and layup, drawing a charge and then making another bucket — all in less than minute.

Marshall added five blocked shots, leading a defense that limited Arizona State to 32.8% shooting.

Arizona State (11-19, 3-15) has lost five straight. Jalyn Brown led the Sun Devils with 17 points and Trayanna Crisp added 16.

The Pac-12 tournament begins in Las Vegas on Wednesday.