How QBR proves Alabama's defensive dominance

Tim Williams and the Alabama defense have shut down opposing quarterbacks all season, but face their toughest test in their final game. Todd Kirkland/Icon Sportswire

After the Chick-fil-A Peach Bowl, Washington quarterback Jake Browning may be seeing Alabama defenders in his nightmares.

Browning took a career-high five sacks, threw two interceptions and posted his worst unadjusted QBR of the season in Washington's 24-7 loss to the Crimson Tide.

"They're very fast," Browning said after the game. "That's the best defense we've gone against."

Browning is just the latest in a long list of starting quarterbacks who have struggled against Alabama's vaunted unit. Beginning with Max Browne's cringe-worthy performance on Kickoff Weekend and extending through SEC play and the College Football Playoff, nearly every quarterback to go up against Alabama's defense has left deflated and dejected.

Consider that 13 different FBS quarterbacks have started against the Crimson Tide and only one (Ole Miss' Chad Kelly) had an above-average QBR performance (greater than 50) before adjusting for the strength of Alabama's defense. Of those 13, seven posted a raw QBR below 10 (out of 100) and nine posted a raw QBR below 20.

Further, those starters had an average raw QBR of 18.6, nearly 45 points lower than their season averages against all other defenses. They took 47 combined sacks and were responsible for eight more turnovers than touchdowns against the Tide.

What makes Alabama's QBR run even more impressive is the strength of opposing quarterbacks faced. Browning (Washington), Kelly (Ole Miss), Joshua Dobbs (Tennessee), Nick Fitzgerald (Mississippi State) and Mike White (Western Kentucky) all rank in the top 20 in Total QBR this season. All of those players (with the exception of Kelly) posted a raw QBR at least 65 points below their season averages against Alabama.

Once adjusting for the strength of opposing quarterbacks faced, Alabama not only leads the country in defensive QBR this season, but it is on pace to post the best defensive QBR for a team since we started tracking it back in 2004.

Of course, the Crimson Tide have not faced their toughest test yet -- a rematch with Deshaun Watson. In last year's title game, Watson accounted for 478 total yards -- the most ever in a national championship game -- and posted a 69 unadjusted QBR in defeat. That number was adjusted upward to 93 once accounting for the strength of Alabama's defense last season.

Watson plays his best in the biggest games and Alabama's defense plays its best in, well, just about every game. If the Crimson Tide can shut down Watson this time around, there should be no question about which defense is the best in recent history.