James was no factor as USC raced to a 37-24 halftime lead. His struggles continued in the second half when Hadley had 10 points and Colorado took over. James was 0 for 7 from the field, with three shots coming from three-point range. He had two rebounds and an assist in 25 minutes.
Cody Williams scored 13 points for the Buffaloes (12-5, 3-3 Pac-12), who ended a three-game losing streak. Tristan da Silva and Eddie Lampkin both scored 12.
Colorado improved to 10-0 at home and got its 500th victory in the CU Events Center.
Oziyah Sellers had a career-high 18 points for the Trojans (8-9, 2-4) and Kobe Johnson, DJ Rodman and Vincent Iwuchukwu all scored 10.
USC was without Boogie Ellis, Isaiah Collier and Joshua Morgan. Ellis (18.7 ppg) strained a hamstring a week earlier but played in the Trojans’ previous game. That’s when Collier (15.4) suffered a hand injury that will keep him out four to six weeks. Morgan (69% shooting) missed his second game because of a respiratory infection.
Colorado was up 59-55 with three minutes to go when Williams scored in the lane. Simpson drilled a key three-pointer with 1:13 to go and Lampkin had a monster dunk at 48 seconds, when USC coach Andy Enfield picked up a technical. Williams made a free throw to finish the clinching 9-0 run.
Colorado shot five for 15 over the last seven-plus minutes and still finished at 56% in the second half (18 for 32). The Trojans were seven for 29 (24%) in the second half with 10 turnovers.
Sellers matched his career high in the first half with 16 points when the Trojans took a 37-24 lead. Colorado, a team that shoots just a fraction over 50%, was nine for 29 (31%).
Sellers had four points to start a 12-0 run that was capped by Johnson’s three-point play for a 27-11 lead at the 8:42 mark.
The Buffaloes had a late 9-3 surge to get within 10, but Sellers came up with five points just before halftime.
Colorado scored six quick points out of halftime and turned that into a 12-2 surge, closing within 39-36 on a layup by Da Silva. The Buffaloes tied the game on a fastbreak layup by Julian Hammond III and after Kijani Wright scored for USC, Luke O’Brien put Colorado up 46-45 with a three-pointer, the Buffaloes’ first lead since 9-8.
Colorado stays home to face the Oregon schools, starting with the Ducks on Thursday. USC goes on its Arizona swing, starting with the No. 8 Wildcats on Wednesday.