Clemson vs. Alabama: Key Matchups in CFP National Championship 2017

It was supposed to be this way.

Ever since Alabama outlasted Deshaun Watson and Clemson in last season's College Football Playoff National Championship, 45-40, college football has been building toward a rematch. It is the unstoppable force that is Crimson Tide football against the quarterback who diced their defense for 405 passing yards, 73 rushing yards and four touchdowns in last year's matchup.

Nick Saban's program has won four of the last seven national titles, but Clemson looked just as dominant in a 31-0 beatdown of another blue-blood program in Ohio State during the Fiesta Bowl.

Chad Peltier of Football Outsiders called the impending game a battle of "the country's most talented team against probably the country's most talented quarterback."

While Watson's showdown with the ferocious Alabama defense will generate plenty of headlines, it isn't the only matchup within the matchup that will prove critical. Here is an in-depth look at a few of them.

Clemson's Offensive Line vs. Alabama's Front Seven

There are few offensive lines as effective as Clemson's, and it will need to play its best game of the season to beat Alabama.

According to Football Outsiders, the Tigers are second in the nation in adjusted sack rate ("opponent-adjusted version of a team's sack rate") and first in passing downs sack rate ("unadjusted sack rate for passing downs pass attempts").

However, that group will face a stiff test in Alabama's defense, which ranks first in the country in rushing yards, total yards and points allowed per game.

Defensive lineman Jonathan Allen is arguably the best defensive player in the nation and has 9.5 sacks and 15 tackles for loss this season, per Sports-Reference. Allen anchors the attack up front, but Alabama has plenty of playmakers with Reuben Foster, Ryan Anderson and Tim Williams, among others.

The Crimson Tide are second in the nation with 50 sacks and will look to unleash constant pressure on the Tigers.

The Associated Press (h/t ESPN.com) noted the Crimson Tide held Washington to a season-low in points (seven) and yards (194) in the Peach Bowl even though the Huskies took the initial lead. 

For as talented as Watson and running back Wayne Gallman are on Clemson's side, the offense won't have much chance if it can't prevent Alabama's front seven from consistently attacking the backfield. If there is any offensive line in the country primed to do so, it is Clemson's, and its performance will impact every offensive snap the Tigers take during the game.

Clemson's Wide Receivers vs. Alabama's Secondary

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For as overwhelming as Alabama is on the defensive side of the ball, it is 15th in the nation in passing yards allowed per game. While that is still an impressive figure, it is not quite machine-like a la the rest of the Crimson Tide's defensive totals.

It happened way back in September, but Alabama's pass defense looked particularly vulnerable when Chad Kelly threw for 421 yards, three touchdowns and zero interceptions in the Crimson Tide's 48-43 win over Ole Miss. Kelly has talent, but he is no Watson, who was a Heisman Trophy finalist and has 4,173 passing yards and 38 touchdown throws on the season.

However, Watson gives opposing secondaries opportunities, and he has 17 interceptions on the season, two of which came against Ohio State. Marlon Humphrey and Alabama's secondary may have chances to turn the game around with turnovers, and Anderson notched a pick-six in the win over Washington.

Despite the interception issues, Watson will have arguably the best group of pass-catchers in the country at his disposal.

Mike Williams has 1,267 receiving yards and 10 touchdown catches, and Deon Cain, Artavis Scott and tight end Jordan Leggett each boast more than 600 receiving yards. Even Hunter Renfrow has four touchdown receptions.

Most teams have just one or two players that a defense truly needs to key on, but Clemson is loaded with playmakers all over the field. Alabama is the most formidable defense in the country, but Watson had little trouble moving the ball against it last year, and he didn't have Williams available.

If the Crimson Tide are forced to double-team Williams, it will open up the other receivers or running lanes for Gallman, who has 1,087 rushing yards and 16 touchdowns on the ground. That formula could lead to another shootout, much like last season's battle.

Alabama's Rushing Attack vs. Clemson's Defensive Line

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From a pure numbers perspective, Alabama is 11th in the nation in rushing yards per game, while Clemson is 22nd in rushing yards allowed per game. However, statistics don't fully encapsulate how demoralizing the Crimson Tide can be when they keep the ball on the ground.

Bo Scarbrough looks more like a defensive lineman than a running back at 6'2" and 228 pounds, and he has the power to run straight through defenders. He also has the elusiveness and speed to burst into the open field, and he is fresh off 180 rushing yards and two scores on 19 carries against Washington in the Peach Bowl.

The Tigers also have to worry about him getting the ball plenty given Saban's comments, per the AP: "Whoever's hot, that's who's going to get the ball. He's been hot lately and he's going to get the ball."

Scarbrough's talent was on full display when Alabama was up just 17-7 in the fourth quarter of the Peach Bowl and facing a critical 3rd-and-9 on its own 3-yard line. He powered his way forward for 12 yards and then exploded for a 68-yard touchdown run three plays later to ice the win.

Scarbrough's potential isn't even accounting for Damien Harris or quarterback Jalen Hurts, who have 1,016 and 891 rushing yards, respectively.

Alabama's defense is as good as it gets, but it will have the best chance to win if its offense dictates the tempo on the ground and keeps Watson and the loaded Clemson attack on the sideline.