TAMPA, Fla. (AP) _ Backup quarterback Marquel Blackwell scored on a 48-yard keeper to highlight South Florida's 17-10 Division I-AA victory Saturday night over Southwest Texas State.

Blackwell replaced starter Glen Gauntt after only two drives in the first quarter and finished with a game-high 57 rushing yards. Blackwell was 8-of-18 passing for 100 yards and one interception at muddy Raymond James Stadium.

Gauntt completed two of his three passes for 21 yards.

Neither team threatened to score in the first half, played in a driving rain as many in the crowd of 26,282 sought shelter.

The Bulls and the visiting Bobcats managed only 58 and 62 yards, respectively, of total offense by halftime.

Only a light rain was falling 64 seconds into the second half when South Florida free safety Anthony Henry intercepted a Spergon Wynn pass and ran 12 yards for a touchdown.

Wynn redeemed himself six minutes later with a 3-yard scoring pass to tight end Eric Diogu, making it 7-7. Safety C.J. Carroll blocked a punt to set up the five-play, 22-yard drive.

All-American Bill Gramatica put the Bulls ahead for good with a 21-yard field goal on the ensuing drive. Blackwell scored his touchdown with 45 seconds left in the third quarter.