BATON ROUGE, La. — LSU roared back from 28 points down to beat Troy, completing the biggest comeback in school history when Charles Scott scored with 4:50 left to put 19th-ranked LSU ahead for good in a 40-31 win tonight.

Troy went up 31-3 midway through the third, but LSU (7-3) answered with a touchdown late in the quarter and then ran off 30 points in the fourth to avoid an embarrassing loss.

LSU had touchdowns on three consecutive possessions to cut Troy's lead to 31-24 with 10:33 left.

The go-ahead score was set up when a punt bounced off the leg of Troy's Jorrick Calvin and the Tigers recovered at the Trojans' 16. Scott scored four plays later after about two-thirds of the fans had left by the end of the third quarter.

The Tigers led 33-31 after Scott scored and Colt David missed the kick. Quinn Johnson scored his second touchdown with about two minutes left to finally put the Trojans at a safe distance.

Levi Brown completed 34 of 72 passes for 312 yards and two TDs Troy (6-4), which scored touchdowns on its first two possessions and was seeking its second victory against an SEC team. LSU avoided its first loss to a Sun Belt team in 33 games.

LSU's Scott finished with 91 yards rushing and Jarrett Lee completed 20 of 34 passes for 217 yards and a touchdown to Brandon LaFell.

David kicked two field goals for the Tigers.