Oklahoma's offense vs. Clemson's defense could be the Playoff's most entertaining matchup

1. Almost exactly a year ago, Clemson whooped Oklahoma in the Russell Athletic Bowl.

The final score was 40-6, and it could have been worse. The significance on the scoreboard was obvious, but it turned out to be significant for the future of both teams.

For Clemson, it was another shot in the arm for a program that has had plenty. The Tigers went 22-4 in 2012 and 2013, complete with bowl wins over brand-name teams (LSU, Ohio State) and lofty rankings (11th in 2012, eighth in 2013). After replacing large chunks of their offense heading into 2014 and dealing with QB injury issues -- all-world freshman Deshaun Watson basically injured every limb -- Clemson still managed to finish 10-3 and squeeze into the year-end top 15.

Riding a streak of four 10-win seasons and bringing back a healthy Watson, the Tigers' run only picked up steam in 2015. Despite rebuilt lines, Clemson went 13-0, debuting at No. 1 in the Playoff rankings and remaining there.

Since the 2012 Orange Bowl loss that prompted head coach Dabo Swinney to replace his defensive coordinator with Oklahoma's Brent Venables, Clemson is 45-7 with a fourth straight top-15 finish, an ACC title, and at worst, a spot in the second Playoff. The Russell Athletic win was proof this train could roll despite turnover.

For Oklahoma, the Russell Athletic loss might have been even more significant. Stagnation had set in, and while Bob Stoops was still the most consistent winner this side of Tuscaloosa -- OU's 8-5 2014 was only the third time in 15 seasons he finished without double-digit wins -- change was needed.

Last year's offensive co-coordinators (Josh Heupel and Jay Norvell) would have probably done well with the influx of talent: quarterback transfer Baker Mayfield (who finished fourth in the Heisman voting), redshirt freshman utility man Joe Mixon (749 rushing yards, 345 receiving yards), JUCO transfer Dede Westbrook (674 receiving yards), freshman tight end Mark Andrews (six touchdowns), etc., were new to the lineup. Sterling Shepard (1,201 receiving yards, 11 touchdowns) managed to stay healthy; he didn't in 2014.

Still, with a deeper battalion, new coordinator Lincoln Riley pulled strings like a master. A new batch of assistant coaches found chemistry in short time.

OU has benefited from each of its last two losses. Another baffling fall -- this one to Texas in early October -- led to some shifts on the offensive line and in the secondary, and the OU of the last two months of the regular season was as strong and steady as anybody.

2. Baker Mayfield likes to run. He's gonna have to.

Mayfield does love to run around. The playmaker from Austin put the fun into Riley's offense, making all sorts of plays. He rushed for 582 non-sack yards and seven touchdowns, and in and out of the pocket, he completed 69 percent of his passes for 3,389 yards, 35 touchdowns, and only five picks.

Despite a dreadful line performance, Mayfield almost single-handedly brought the Sooners back against Texas, and in the seven games after, his stat line went to ridiculous: 71 percent completion rate, 21 touchdowns, two interceptions, 183.9 passer rating. He suffered an apparent head injury against TCU but passed concussion protocol and completed 17 of 25 passes in the Big 12-clinching win over Oklahoma State.

Mayfield almost earned a trip to New York. (Many thought he should have.) But his rambler-gambler routine has a downside: sacks. He took 34, and OU's Adj. Sack Rate ranked 104th. That could be a scary proposition against Clemson.

Clemson's defense is absurdly disruptive. The Tigers rank first in the country in stuff rate (run stops at or behind the line) and produced a sack rate of 11.5 percent on standard downs (first) and 9.3 percent on passing downs (28th). In those categories, Oklahoma's offense ranks 49th, 120th, and 87th, respectively.

At third in Off. S&P+, the Sooners' offense is the best Clemson has faced this year, but Clemson's defense ranks sixth in Def. S&P+, and the disruption factor could be significant. Mayfield can run for his life as well as anybody, but you don't want him to do it every time.

3. Clemson's efficient offense vs. Oklahoma's efficient defense

Most of Oklahoma's problems in last year's bowl came on the offensive side. After a 65-yard touchdown pass on the first play, Clemson only averaged 4.1 yards per play the rest of the way. The passing game was used mostly for efficiency, and running back Wayne Gallman gained only 55 yards in 19 carries.

Of course, it bears mentioning that Watson didn't play. Clemson's offense was infinitely better with Watson last year than Russell Athletic starter Cole Stoudt.

The approach is similar, though. Watson averaged only 12.2 yards per completion this year, and while there are big-play weapons -- though Deon Cain is suspended, receivers Charone Peake and Hunter Renfrow have caught five passes per game at 14.6 yards per catch -- leading receiver Artavis Scott is basically a tight end, with an 80 percent catch rate and only 9.9 yards per catch. In the run game, Gallman has gained at least five yards in 40 percent of his carries but hasn't broken many huge gains.

This is an efficiency offense, but OU's defense ranks eighth in Success Rate+, or preventing efficiency*. Even with Watson's presence, the Sooners might be able to keep Clemson in check unless someone like Peake or Renfrow breaks a big gain.

* This ranking is at least a hair inflated because of quarterback injury. The Sooners played Baylor after Seth Russell was lost, took on a Trevone Boykin-less TCU, and faced Oklahoma State a week after Mason Rudolph suffered an ankle injury. It's important not to overreact, but a more hand-crafted defensive efficiency ranking would place OU about 10th or 15th.

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Check out the monstrous stat preview here.

Spread: Oklahoma -4

S&P+ Projection: Clemson 30.5, Oklahoma 28.7

Team Sites: Crimson And Cream Machine, Shakin The Southland

4. Key Stat No. 1: OU big plays

Category	Oklahoma offense	Clemson defense
EXPLOSIVENESS	1.41 (7)	1.40 (114)
EFFICIENCY	46.8% (17)	31.2% (3)

Venables' Clemson defenses have been as impressive as anyone's when it comes to the break-don't-bend model. Defenses like Clemson's, Michigan State's, and Baylor's have come to the conclusion that risking the occasional big play is fine if the reward is three-and-outs and turnovers. Your big-play ratings can be awful if your success rates are awesome.

That Clemson is 13-0 and No. 1 is proof this can work. But the big plays the Tigers allow are enormous. They have allowed only 142 gains of 10-plus yards (20th in the country), but 18 have gone for at least 40 (101st).

Oklahoma produced 19 40-yarders in 12 games, and the Sooners' big-play ratings are as good as almost anyone's. Shepard and Westbrook have combined to average 10 catches per game and 15.5 yards per catch, and both Samaje Perine and Mixon are well above average in open-field skills.

The difference could be how many big gainers OU produces. Clemson is great at pushing you backwards, but how frequently does the dam break? Mayfield can live with some sacks if he can snap off three huge passes.

5. Key Stat No. 2: Clemson on first down

Standard Downs

	Clemson Offense		Oklahoma Defense
	Avg.	Rk	Avg.	Rk	Edge
Standard Downs S&P+	124.7	6	127.4	3
Standard Downs Success Rate	52.7%	16	40.5%	15
Standard Downs IsoPPP	1.23	16	1.08	35	Clemson
SD Line Yards per Carry	3.25	19	2.55	23
SD Sack Rate	1.6%	7	6.1%	31	Clemson

Looking at the giant stat preview above illustrates how close many of the matchups are. But none is more even than Clemson's standard downs offense vs. Oklahoma's standard downs defense. Clemson is as good as anybody at staying ahead of the chains, but Oklahoma's speed has allowed the Sooners to knock teams off-schedule.

While the game could end up volatile when Oklahoma has the ball -- big plays, negative plays -- Clemson's offensive possessions will likely be less dramatic. If Gallman is gaining four or five yards on first down, and Watson is able to work off of that (he completed 77 percent of his passes on first down), the Tigers will put points on the board. But if Clemson is falling into second-and-9 or third-and-7, OU's well-rounded defense should get enough stops.

On paper, this is about as even a game as you could hope to watch, if you have no rooting interest. This should be a fascinating semifinal.