After falling behind 7-0, Thornton (5-1, 1-1) tied the game on a one yard touchdown run from Keynan Hugley.
Nathan Morales returned the ensuing kickoff 85 yards for a touchdown. Brighton (5-1, 2-0) never trailed again.
Down 21-7 at the break, Thornton went 99 yards on 12 plays to start the second half, capped by Hugley’s second touchdown run.
Brighton answered by covering 80 yards on two plays, both passes from Ethan Trujillo to Tristan Wells.
Brighton hosts Prairie View next Friday at 7 PM.
Thornton will also be at home against Northglenn next Friday at 7 PM.