It was South Florida's first win against an SEC opponent since 1995. Jarrid Famous led the Bulls (6-5) with 15 points.
Andre Malone scored 18 points and Earnest Ross 11 for Auburn (3-6).
But the Tigers welcomed back Sullivan, who underwent left knee surgery on July 27. Although Auburn didn't explicitly rule the junior out for the season, he wasn't expected to contribute until the 2011-12 season.
Sullivan, the team's leading returning scorer (12.7 ppg) and rebounder (3.7 rpg) from last season, went 1-for-3 from the field and scored all four of his points on a four-point play just before halftime. He added two steals and two assists.
Auburn plays again Saturday at home against Presbyterian. Tipoff is 8 p.m. ET.