Booker added seven rebounds and four assists while going 9-of-17 from the field for the fifth-seeded Buffaloes (22-10), who will take on California in Thursday's quarterfinals. Josh Scott tallied 13 points and nine rebounds in the win.
Byron Wesley finished with a game-high 23 points for USC (11-21), which tied the contest at 50-50 with seven minutes left before Scott netted the first six points of an 8-0 Colorado run that Booker capped with a successful layup with 3:07 to play.
The Buffalos didn't make a field goal the rest of the way, however, and the Trojans closed within 59-56 when Wesley drove and scored with 47 seconds left.
Scott then missed from in close on the ensuing possession, but Colorado survived when Wesley's 3-point try that would have forced overtime landed off the mark.
USC ended a poor 5-of-22 from beyond the arc and was outrebounded by a 38-27 margin.