The Volunteers (2-2) had held a 23-7 lead at halftime. But the Blazers (1-3) staged their second major comeback in two weeks as David Isabelle found Frantrell Forrest on a 27-yard touchdown strike and ran for 6 yards for another score and Bryan Ellis hit Jeffery Anderson on two 2-point conversions.
Daniel Lincoln kicked a 40-yard field goal for Tennessee to open the first overtime, and UAB's Josh Zahn, who missed field goals from 30, 35, 41 and 49 in regulation, connected on a 35-yard field goal to answer.
Ellis hit Pat Shed on a 14-yard pass to pick up a first down in the second overtime but his 7-yard pass to Patrick Hearn came up 4 yards short of the end zone, and Zahn scored on a 21-yard field goal to put UAB up 29-26 before the Vols' final touchdown. The Blazers dominated the game in nearly every category. They picked up 544 yards compared to the Vols' 287 yards, had eight more first downs and converted seven more third down attempts.
Tennessee's defense couldn't stop UAB, who used Isabelle, the backup quarterback, to chip away yards with his runs and Ellis, the starter, to convert third-and-long situations.
Ellis completed 29 of 55 for 373 yards, a touchdown and an interception. Isabelle ran 16 times for 73 yards and completed 4 of 5 for 56 yards and a touchdown.
Still, the Vols seemed to be in control in the first half. The Vols went for it on fourth-and-1 at the UAB 15 on its first drive and got two yards on a quarterback sneak by Simms, who threw a 13-yard touchdown pass to Moore on the next play.
UAB had just tied the game at 7 with a 52-yard touchdown pass from Bryan Ellis to Mike Jones with 2:34 in the first quarter, but Simms answered with a 72-yard touchdown to Zach Rogers on the next play. It was Tennessee's longest play since an 87-yard touchdown run by LaMarcus Coker against Vanderbilt in 2006.
With 1:55 before halftime, Chad Cunningham backed up UAB with a 54-yard punt to the Blazers 5, and Prentiss Wagner picked off Bryan Ellis on the next play and returned it 9 yards for a touchdown.