GLENDALE, Ariz. -- To win a national championship is one thing. To repeat is another.

Alabama's offense has been impressive all year long, but Tuesday night at University of Phoenix Stadium it was the Crimson Tide's defense that once again kept its record unblemished.

Undefeated and top-ranked Alabama kept a lid on No. 2 Ohio State's explosive offense, and the Tide repeated as national champions with a 24-10 victory in the BCS National Championship game.

Alabama quarterback Blake Sims and halfback TJ Yeldon have both enjoyed an All-American offensive line in 2014 to help power the Crimson Tide's point-scoring efforts. But time and time again it was the defense doing its job to turn big games into blowouts.

2013 Heisman Trophy winner Braxton Miller's scrambling was problematic in the beginning. He'd finish with 100 yards rushing and a touchdown, but the Buckeyes (13-1) amounted to nearly nothing in the second half, especially the fourth quarter.

Ohio State made it into the red zone three times in the second half of what was only a two-score game, but they were turned away each time by the Tide's defense, only mustering a point-blank 17-yard field goal on their first possession after halftime.

Miller would have been kept out of the endzone completely if it wasn't for the Alabama defense stopping itself. True freshman cornerback Terry Swain had a beat on Braxton in the second quarter to make a stop and give the Tide a chance at another red zone stand, but fellow corner Jabriel Washington tripped up Swain, allowing Braxton to run free and score OSU's lone touchdown.

That touchdown made it 10-7 Alabama, but the Tide answered in the last minute of the opening half with a touchdown to make it 17-7 at halftime. Alabama then turned out another TD to open the third quarter, making it a seemingly insurmountable 24-7 --- especially with the Tide defense to try and get through.