Manziel, the reigning Heisman Trophy winner, threw four TD passes, including a scoring strike to Mike Evans late in the third quarter that gave the Aggies a 31-24 lead. But he left the field with a shoulder injury and backup Matt Joeckel guided Texas A&M to a 20-yard field goal from Josh Lambo for a 10-point advantage at 34-24.
The Tigers (6-1, 3-1 SEC) came back with consecutive scoring drives, capped by touchdown runs from Nick Marshall and Cameron Artis-Payne, giving Auburn a 38-34 lead with 9:06 left in the game.
Manziel returned to the game, engineering a 12- play, 75-yard push topped by a 1-yard TD run for a 41-38 Aggies lead with 5:05 remaining.
The contest was decided on the next series, when Marcus Davis made a 27-yard catch down the right sideline and Mason went up the middle for a 5-yard TD with 1:19 remaining.
Manziel had one shot left, but the Aggies (5-2, 2-2) fell short when the quarterback was sacked on fourth-and-13 from the Auburn 21-yard line as time ran out.