Garrett Sim scored 20 points and Oregon made five 3-pointers in the second half to hold off USC 65-62 Thursday night.
Devoe Joseph added 16 points and Olu Ashaolu had 11 for the Ducks (14-5, 5-2 Pac-12), who have won three straight and are off to their best start since going 18-1 in 2006-07.
Maurice Jones scored 22 points for the Trojans (5-14, 0-6), who haven't been winless this deep into conference play since opening 0-12 in 1989.
Dewayne Dedmon also had a season-high 18 points and seven rebounds for USC.
Oregon led 30-28 at halftime and never was able to build more than an eight-point lead in the second half. The Ducks were up just 56-54 with 2:40 to play following a three-point play by Dedmon. But Joseph answered with a 3-pointer to make it 59-54, and Oregon closed it out by hitting six straight free throws in the final 1:40.