Mason's 1-yard touchdown run capped a 79-yard, 11-play drive at the start of the fourth quarter and put the Bulldogs (7-2, 6-1 Southwestern Athletic Conference) ahead to stay.
Alabama A&M got the ball back at its 44 when Preston Nelson stopped Arnold Walker of the Braves (2-6, 1-6) for a 1-yard loss on fourth-and-1. The Bulldogs then drove 55 yards on eight plays, with Lacey scoring from 8 yards out.
Two big defensive plays helped the Bulldogs end the first half tied 14-14.
After Rico Porch returned a fumble by Walker 49 yards to tie the game at 7, Clarence Morris intercepted Darius Smith's pass on the next play and returned it 30 yards to score.
Anthony Williams' 54-yard run for the Braves tied it with 3:55 left in the half.