ATLANTA (AP) -- Auburn and Missouri are competing for the Southeastern Conference title Saturday, and possibly a chance to play for the national championship.

Yet both teams have to guard against a letdown.

As ludicrous as that might sound, Auburn and Missouri are coming off emotionally charged victories last week that gave each coach a reason to fret just a bit.

No. 3 Auburn (11-1, 7-1 SEC) used one of the greatest finishing plays in college football history -- a 109-yard return of a missed field goal with no time on the clock -- to beat two-time defending national champion Alabama in the Iron Bowl for the West Division title. No. 5 Missouri (11-1, 7-1) won the East with a thrilling victory of its own, knocking off Heisman Trophy winner Johnny Manziel and Texas A&M 28-21.

Auburn must get past one of the most improbable victories ever, beating its biggest rival in a game that likely eliminated the Crimson Tide from its quest for an unprecedented third straight national title. Auburn coach Gus Malzahn watched the frenzied crowd storm the field at Jordan-Hare Stadium, then urged his team to get right back to work.

The winner could get a shot to play for the SEC’s eighth straight national title, but that will depend on what happens in Charlotte and Indianapolis.

Top-ranked Florida State (12-0) is a huge favorite against Duke in the Atlantic Coast Conference championship game, while second-ranked Ohio State (12-0) figures to face a much tougher challenge against Michigan State in the Big Ten title game. If both win, that will likely set the matchup for the BCS championship. If either falters, the Auburn-Missouri winner can expect to land a trip to Pasadena.

RUN, AUBURN, RUN: Malzahn’s team has one of the nation’s most prolific running games, centered on quarterback Nick Marshall and junior back Tre Mason. Auburn’s hurry-up spread formation incorporates elements of old-school offenses such as the wishbone, but can strike suddenly with its lesser-used passing attack.

OVERLOOKED D: Auburn’s defense plays in the shadow of the team’s explosive offense but has come up with huge stops in the red zone. It stopped Georgia’s Aaron Murray at its own 20 to preserve a 43-38 victory, and kept Alabama from converting on fourth-and-1 in the fourth quarter, which made it possible for the Tigers to pull off the amazing finish.

DISRUPTIVE SAM: Missouri’s defense is led by end Michael Sam, who leads the SEC in both sacks (10.5) and tackles behind the line of scrimmage (18).

CARDIAC AUBURN: Auburn feels like a team of destiny. Malzahn’s group pulled out an improbable victory over Georgia with a 73-yard touchdown pass on fourth-and-18 in the final minute -- a play that looked doomed until two Georgia defenders collided going for the interception, deflecting the ball ahead to Ricardo Louis, in stride, for the winning score. The victory over Alabama was even more unlikely.