Tevin Washington threw a touchdown pass and ran for another score to lead Georgia Tech to a 21-7 victory on Monday in front of a crowd of 47,922 at Sun Bowl Stadium.
Washington's 1-yard touchdown run in the third made it 14-7, and he found Orwin Smith for a 17-yard touchdown pass in the fourth.
Barkley, the first three-time captain in team history, injured his right shoulder in a loss to UCLA and was not cleared to play.
His replacement, Max Wittek, tossed a 9-yard touchdown pass to Silas Redd in the second quarter, but also threw three interceptions. Redd also had 88 yards rushing on 17 carries.
The Trojans (7-6) struggled to contain Georgia Tech's triple-option attack. The Yellow Jackets (7-7) rushed for 294 yards on 63 carries while stopping a seven-bowl losing streak.
David Sims had 99 yards on 17 carries, but he got plenty of help. Zach Laskey added 60 yards on six carries, Lee had 52 on 10 carries and Washington had 16 attempts for 46 yards for the No. 4 rushing team in the nation.
Sims also caught a 3-yard touchdown pass from Vad Lee in the first quarter.
Lee and Washington combined to go just 5-for-10 passing, but two completions went for TDs passes and two more covered 26 and 49 yards and keyed two of the team's scoring drives.
Georgia Tech shut down the Trojans' big-play threats all afternoon, and high-powered USC finished with only 10 first downs and eight punts.
Wittek had four passes deflected at the line. His second interception came in the Georgia Tech end zone with 6:22 to go and the last came inside the Yellow Jackets' 10-yard line in the game's final minute. He was 14-for-37 for 107 yards.