South Carolina won its sixth consecutive game and the defense didn't allow a touchdown for the second in a row.
That streak - and South Carolina's perfect start - will get severely tested next week with a trip to No. 2 LSU.
The numbers looked strong for South Carolina.
Mitchell finished 14 for 21 for 147 yards. Cory Boyd (132) and Mike Davis (102) went over 100 yards rushing, but the Gamecocks' offense looked lost for a half against the Bulldogs (1-2).
Mitchell had three interceptions and a fumble to go with his touchdown throws. Backup Tommy Beecher added an interception and a fumble of his own.
It got so bad, Gamecocks coach Steve Spurrier chose to run the ball much of the second half. And that's when South Carolina finally put away its Championship Subdivision rivals.
Davis rushed for 43 yards and finished a 91-yard TD drive with a 9-yard catch from Mitchell.
Two series later, Boyd broke free for a 29-yard scoring run and the Gamecocks were up 31-3.
Spurrier called only two passes in the third quarter. Then again, he didn't have to get creative the way South Carolina's defense played.
The Gamecocks picked off three passes of their own, lineman Nathan Pepper returning one 19-yards for a touchdown to put them ahead for good, 7-3.
South Carolina State had just 46 yards passing through three quarters.