Hardesty ran for two touchdowns on 23 carries for 121 yards, while Chad Cunningham kicked a fourth-quarter field goal for the Volunteers (4-4, 2-3 SEC), who compiled four turnovers but lost the total offense battle 365 yards to 341.
South Carolina's Stephen Garcia completed 25-of-50 passes for 300 yards, one touchdown and one interception.
Spencer Lanning kicked two field goals.
Kenny Miles had 44 yards and 44 receiving, while Moe Brown, Alshon Jeffery and Tori Gurley all caught four passes for 54 yards with Brown catching a third-quarter touchdown pass for the Gamecocks (6-3, 3-3), who sank to 1-14 all-time at Neyland Stadium.
Attkisson leaves CBS News, reportedly over network's 'liberal bias'
Duggar sisters unveil Christian dating rules in new book