One year ago, the Oklahoma Sooners fielded the worst defense to ever qualify for the College Football Playoff. Under first-year head coach Lincoln Riley, and behind Heisman Trophy-winning quarterback Baker Mayfield, Oklahoma took a 17-point lead on Georgia, the eventual national runner-up, before losing in the Rose Bowl semifinal. Twelve months later, Riley has another Heisman-winning quarterback in Kyler Murray and has piloted another one-dimensional Sooners team to a playoff berth.

The reward — a date with Alabama, college football’s lead power broker — seems more like a punishment. The Tide, long a defensive force under coach Nick Saban, now boast what’s likely the best offense in program history. Las Vegas oddsmakers cared not for Oklahoma’s three-game winning streak against the Tide and opened with Alabama as two-touchdown favorites. According to FiveThirtyEight’s college football prediction model, Alabama has a 41 percent probability of winning the national title. Oklahoma faces much taller odds, with an 11 percent probability of winning it all.

Here’s what to look for the when the two programs meet in the Orange Bowl semifinal Saturday at 8 p.m. Eastern.

Will Tua Tagovailoa or Kyler Murray win the QB showdown?

Seldom do a Heisman winner and his runner-up meet after the winner is crowned. Even given that rarity, this may be the best postseason clash of college quarterbacks we’ve ever seen. Both are coming off of historic regular seasons, with each in line to trump the record for Total Quarterback Rating, which ESPN has tracked since 2004 and is measured on a scale of 0 to 100.

But it’s not just the quarterbacks. In terms of offensive efficiency, this is the best matchup since the playoff began in 2014. Oddsmakers have taken notice, setting a points over/under total that’s unprecedented in the playoff era.

It seemed logical that the departure of Mayfield, the No. 1 pick in the 2018 NFL draft, would abate Oklahoma’s offensive horsepower. That 2017 team had the most efficient offense ever tracked, according to the ESPN Stats & Information Group. But in Murray’s first full season as a starting college quarterback, the Sooners’ offense has actually improved. “Kyler Murray has accomplished more in one season and had more impact on the Sooners’ tradition in one season than any other player in our history,” former Oklahoma coach Barry Switzer told The Athletic. “He’s broke all the damn records.”

The Sooners have gotten better under Murray Oklahoma’s offensive production in 2018, with Kyler Murray at quarterback, vs. 2017, with Baker Mayfield at quarterback Metric 2018 2017 Offensive points per game 47.0 43.6 Yards per play 8.8 8.3 Percentage of first downs or TDs per play 41.0% 37.6 Percentage of first downs or TDs per pass attempt 51.1% 49.4 Percentage of plays for zero or negative yards 25.6% 26.6 Source: ESPN Stats & Information Group

As if spring-loaded, Murray’s legs have minced opposing defenses. On a 75-yard touchdown run against Kansas, a broadcaster declared, “You’re not going to catch him,” before Murray had passed the 40-yard line. The junior is the country’s pre-eminent dual-threat wizard, whose 892 rushing yards place him seventh among all Football Bowl Subdivision quarterbacks this year.

At the same time, Tagovailoa has been the figurehead of the Tide’s offensive ascension since replacing Jalen Hurts in last season’s national championship game. Saban has been in Tuscaloosa since 2007, and this year’s offense has been his best in terms of, well, everything.

This is Saban’s most dominant Alabama offense Alabama’s offense by season under head coach Nick Saban Per play Per Game Season Yards Yards Passing

Yards 1st Downs Offensive Points 2018 7.92 527.6 325.5 24.6 43.9 2017 6.59 444.1 193.4 22.2 36.1 2016 6.47 455.3 210.3 21.0 31.9 2015 5.89 427.1 227.1 21.9 30.1 2014 6.66 484.5 277.9 24.3 36.3 2013 7.15 454.1 248.5 23.2 34.2 2012 6.95 445.5 218.0 21.6 37.2 2011 6.46 429.6 215.2 21.6 32.1 2010 6.96 444.1 261.2 22.1 33.4 2009 5.96 403.0 187.9 20.6 30.1 2008 5.52 355.8 171.1 18.8 25.6 2007 5.05 373.8 224.5 22.6 26.4 Source: ESPN Stats & Information Group

Both Murray and Tagovailoa are having little difficulty stretching the field. If they keep up this pace during the playoffs, each would rank in the top three among all QBs since 2004 in single-season passing yards per attempt, with Murray’s current 11.92 mark in line to set the all-time record.

They won’t, however, be competing against equally proficient defensive units. Murray will be staring down a top-flight fortress that spent the past few months razing offensive lines and leveling quarterbacks. The Crimson Tide rank second in defensive efficiency, behind Clemson, and they lead the country in adjusted defensive quarterback rating, which accounts for the strength of the opposing quarterback. The Tide ranks among the 15 best teams in opponent completion percentage (51.8 percent) and yards allowed per pass attempt (5.86).

Tagovailoa will have the luxury of playing against a defense that might seem as though it’s providing Alabama an escort to the end zone. Oklahoma ranks 92nd in defensive efficiency, unseating last year’s squad as the new worst defense to make it to the playoff; the Sooners have allowed 56 touchdowns this year, 13 more than Alabama has allowed since the beginning of the 2017 season. Uninspired performances led to the midseason firing of defensive coordinator Mike Stoops. But the unit’s play hasn’t improved. After giving up 39 first downs to Oklahoma State, the most allowed by any FBS team this season, interim defensive coordinator Ruffin McNeill found room to praise his team for making “critical stops.”

Pass defense, in particular, has been ghastly for the Sooners. No FBS team allows more passing yards per game (291.4), and only five allow more completions (22.3). The Sooners love to give up the long play, having allowed 56 passing plays of 20-plus yards, the fourth-most by any team.

It’s unlikely that the turnover margin will favor the Sooners — even though Tagovailoa threw as many interceptions in his last outing as he did the rest of the season total. Oklahoma has generated 11 takeaways all season, the fewest of any qualifying team in the playoff era. Alabama has forced 11 since the beginning of October — and 21 in total.

On the opening drive of the SEC championship game, Tagovailoa suffered a high ankle injury, which required surgery the following day. The sophomore has said that he’ll be unencumbered come game time, and given how little he rushes — generating just the 89th-most rushing yards among QBs — he won’t need much mobility. Even a pocket-locked Tagovailoa can still shred an opposing defense.

Can Oklahoma survive Alabama’s first-half avalanche to win the second half?

Players come and go, and each season carries idiosyncrasies, but the narrative arcs of the Sooners’ two previous playoff appearances were seemingly penned by the same author. In both, a lead evaporated and a dominant first half gave way to a second-half dud.

In those appearances — in the 2015-16 Orange Bowl and the 2017-18 Rose Bowl — the Sooners outscored opponents 48 to 33 in the first half and were pummeled 49 to 14 in the second. Those losses, Riley said, could be traced to physical opponents and conservative play-calling.

Rewriting the script, then, will be paramount this time around for Oklahoma.

Offensively, the Sooners seem to have the first half covered. No team puts up more first-half yardage than Oklahoma, which averages 313.4 yards a game. The team racks up 9.5 yards per first-half play — nearly a first down on each play. Riley’s offense is outscoring opponents by an average of 11.3 points in first halves this season, the eighth-best mark in the country.

Of course, what separates Alabama from Oklahoma is its defense. The Tide allow 7.9 points per game in first halves, 12th-fewest in the nation and 7.9 fewer points than the Sooners. Alabama doesn’t just shut the door on its opponents in the opening 30 minutes — it packs their bags, shuttles them to the airport and ushers them through TSA. Remember when the Tide turned Tiger Stadium into a morgue by the third quarter of November’s top-five showdown with LSU? Or when the Tide took a trip to Oxford, watched Ole Miss score on its opening play and then blitzed the Rebels with 62 unanswered points, including 49 in the first half?

LSU and Ole Miss aren’t alone. Saban’s squad is outscoring opponents 388 to 103 in first halves this season. On average, the Crimson Tide enter the locker room at halftime with a 21.9-point lead, the second-biggest margin by any team since at least 2004, the first year for which data is available. Ninety-three teams have scored fewer total touchdowns than Alabama has scored in first halves. Only four teams in the past 15 seasons have scored more first-half touchdowns than the Tide’s 53.

These lopsided first halves mean that the Tide hardly ever fall behind on the scoreboard. The average college football team this season played 178.6 first-half offensive snaps when trailing. Alabama played 18 — 32 fewer than the next-closest team.

Bama rarely plays from behind Total first-half snaps when trailing for this year’s playoff participants Team Offensive Snaps Defensive Snaps Alabama 18 12 Clemson 63 24 Notre Dame 69 40 Oklahoma 128 54 National average 177 129 Source: ESPN Stats & Information Group

Coming into the SEC title game, teams had run a combined 388 first-half plays against the Tide defense. They didn’t have the lead on any of them. Georgia finally broke through in the SEC championship; the Bulldogs ran 43 first-half offensive plays against the Tide and led for 12 of them.

The nightmare doesn’t end for Alabama opponents in second halves: Then they’re outscored by a touchdown and a half, on average. In second halves, teams score 0.92 touchdowns per game against the Tide, tied for the sixth-fewest.

Conversely, Oklahoma’s dominance tapers off considerably in the final two quarters, when it outscores opponents by only 5.2 points, which ranks 24th nationally.

Little if any of that decline is attributable to the offense, which roars from start to finish. But defensively, the bottom seems to fall out for the Sooners after halftime, as they allow an average of 2.23 touchdowns per game in second halves, the most by any team in the Big 12 and tied for the 20th-most nationally. Riley’s defense has allowed 29 second-half touchdowns, the most by an Oklahoma defense since at least 2004.

However, should Oklahoma keep the game close down the stretch, it has a peerless crunch-time quarterback in Murray. The Sooners have played seven games decided by 14 or fewer points, while Alabama has played only one. In the fourth quarter, when the scoring margin is within 14 points, Murray has a nation-leading quarterback rating of 99 — that’s on a 1-to-100 scale, mind you.

There’s an argument to be made that Oklahoma is better equipped — certainly more experienced — to handle high-leverage situations. But Alabama has been so dominant that it simply hasn’t mattered.