Griffen made a 43-yarder in the first OT, and Jordan Hoy threw a 7-yard score to Mason Sikes in the second extra period for Lamar (4-3, 2-2 Southland Conference). Lawson intercepted a Ty Brock pass to end the game.
Hunter Pinegar kicked a 23-yard field goal in the first overtime, and Donovan Williams ran into the end zone on an 11-yard run in the second for Sam Houston State (4-3, 3-1).
Brock tossed a 5-yard touchdown pass to Nathan Stewart in the first quarter. Lamar's Cameron Houston scored on a fumble recovery in the end zone in the second quarter that tied the game at 7-7 before a scoreless second half.