SLU (4-2, 2-0 Southland Conference) held a 30-8 led in the fourth quarter when Northwestern rallied. Adkins passed to Garrett Atzenweiler to close the gap to 30-22 with 2:44 remaining. Northwestern (2-3, 0-1) then recovered an onside kick. Adkins had his team at the SLU 36 when Thompson intercepted.
Isiah Corbett returned an interception 44 yards for the Lions first touchdown.
SLU led 6-0 on two Ryan Adam's field goals when Corbett scored.
Thompson also intercepted Adkins in the second quarter and returned it 55 yards to stop another scoring threat. Derrick Raymond had the fourth interception for the Lions.
Adams, who booted a school record 55-yard field goal, also had field goals of 41 and 30 yards.