(Photo by Ron Jenkins/Getty Images)

No defense this season has been as dominant nor as steadfast as the Alabama Crimson Tide. This should worry the Clemson Tigers; they do, after all, square off with Nick Saban’s outfit in the College Football Playoff National Championship, pitted against a defensive juggernaut that leads the country in sacks, defensive efficiency and scoring defense.

I mean, they’re as good as it gets,” Clemson head coach Dabo Swinney said recently. “No. 1 in about everything defensively, but the biggest thing is they just have great depth in their defensive line. They roll them guys in there, play a lot of guys, a bunch of subs, and they all play at a really, really high level. That’s why they’re a great team.”

More notable, though, is the red-zone defense deployed by defensive coordinator Kirby Smart, which hasn’t allowed a red-zone score since the first quarter of the team’s win over Auburn more than a month ago. Alabama’s two most recent opponents — Florida and Michigan State — combined to procure one red-zone opportunity, and it ended with an Alabama interception.

Smart has orchestrated a number of historically great Alabama defensive units — the Tide has ranked no lower than seventh in defensive efficiency each season since 2008, the year Smart was promoted to defensive coordinator — but as for this year’s squad, he acknowledged the level of competition they’ve faced could put them at the top of his personal leaderboard: “This team has faced probably better offenses and more talented offenses (than defenses of year’s past). It’s deep.”

Alabama opponents’ red-zone scoring percentage, or the percentage of drives that a team scores once it has reached the opponent’s 20-yard line, is tied for 41st nationally (80 percent), which, while impressive, is considerably amplified when the context of total red-zone opportunities allowed this season is introduced. The Tide has allowed a nation-leading 25 drives to reach its 20-yard line and just 44 percent of them ended with touchdowns; Clemson, for example, has allowed an opponent to reach the red zone 39 times, with 56.4 percent of them ending with touchdowns, and defensive coordinator Brent Venables has watched his defense allow nine touchdowns on those drives over the past three games alone. Smart’s defense has allowed 11 opponent red-zone trips end in touchdowns all season, a mark that’s tied for second nationally.

In total, Clemson’s offense is certainly formidable inside the opponents’ 20-yard line. Deshaun Watson presents a dual-threat challenge for a defense, and the team has converted 60 percent of its red-zone trips this year into touchdowns. The Tigers’ red-zone scoring percentage (89.1) ranks in the top 20, too.

Surprisingly, though, despite Clemson’s offense ostensibly surging at the right time — at least 530 yards of offense, 5.89 yards per play, 37 points in each of the past two games — red-zone struggles have manifested in the month of December for Swinney.

Clemson’s offensive monthly splits show a dip of nearly 10 percent in red-zone scoring percentage from October and November to December. Against Oklahoma, Clemson produced 13 points on four trips inside the Sooners’ 20-yard line in the first half.

Failing to convert lengthy drives into points is a hallmark of innumerable losses in the annals of college football history, but what’s more impressive, at least from a defensive perspective, is a team disallowing the opponent to put together drives at all.

On average, Alabama opponents begin drives 72.8 yards away from the end zone; only 17 teams play with better defensive field position. More than 26 percent of Tide opponents’ drives started inside their own 20-yard line, meaning Alabama has positively dominated the field-position battle this season, spinning the field into a weapon unto its own.

Conversely, Clemson has rarely had to worry about its starting field position this year on account of how explosive Watson and Co. have been — ranking in the top 15 in plays of 10-plus, 20-plus and 30-plus yards. On average, Clemson drives have started 73.1 yards from the end zone, which ranks 120th nationally. Less than 10 percent of the team’s drives started at midfield or on the opponents’ side of the 50-yard line, and Swinney is all but guaranteed to not have the luxury of any short-field drives in the national title game. This means Clemson not only will need to break through Alabama’s steel-plated defense, but then crack its fortress of a red-zone.

It’s a near-miracle for opponents to find success against the Alabama defense and take over inside the Tide red-zone, and it usually takes another miracle to earn those final 20 yards. Clemson’s offense has made mincemeat of opposing defenses all season, but Alabama presents the final hurdle, and it’s unclear if there are any cracks in Smart’s armor for the Tigers to exploit.