Michigan State

On Monday, Clemson and Alabama will face off for the College Football Playoff national championship, a matchup predicted by nearly nobody. Sure, plenty of people picked 'Bama to be in the title game (and you would've been right more than half of the time in the past seven years), but few outside of Clemson saw this quantum leap by the Tigers.

So how did we get here? The Tigers actually are top seeded because they're the only unbeaten FBS team this season. The Crimson Tide, on the other hand, needed a little bit of help to make the four-team playoff. The turn of events took place from coast-to-coast, most of the time on the field, but sometimes in a bathroom.

We took a look back at the 2015 season and found the 10 events most responsible for getting us to this point. Here they are in descending order of importance:

10. (Dec. 5) North Carolina's legal onside kick ruled illegal:

For the first time all season, top-ranked Clemson was reeling. North Carolina had just scored a touchdown with 1:13 left in the ACC championship game to trim the Tigers' lead to 45-37 and then immediately recovered the onside kick with a chance to send the game into overtime.

Except there's one problem: The ACC refs somehow ruled the perfectly executed onside kick illegal -- for no apparent reason. The Tar Heels were flagged for offside, except they weren't. This was not the first or the worst blown call made by an ACC officiating crew in 2015, but it was the most fateful.

9. (Dec. 5) 1-yard run caps epic game-winning drive:

Trailing Iowa 13-9 with 9:31 left in the Big Ten championship game, Michigan State embarked on a 22-play, 82-yard drive that chewed up 8 minutes and 4 seconds that left the crowd, as well as Hawkeyes defenders, gasping for air.

But the game wasn't decided until running back L.J. Scott, on his 14th carry of the drive, bulldozed his way into the end zone from a yard out on third-and-goal, overpowering a couple of defenders who initially had stopped him short of the goal line.

8. (Nov. 28) 45-yard field goal completes 30-second comeback:

Notre Dame had scored a touchdown with 30 seconds left, seemingly planting one foot in the four-team playoff. But for the second time in Brian Kelly's career as the head coach, his Irish team blew a lead with exactly half a minute left in the game (also in 2011 at Michigan).

Stanford drove 45 yards on five plays after the ensuing kickoff, setting up Conrad Ukropina's 45-yard field goal attempt with 6 seconds left. Ukropina's kick split the uprights as time expired, giving the Cardinal a 38-36 victory and knocking the Irish out of the playoff.

7. (Nov. 21) TCU's failed two-point conversion:

The Horned Frogs had rallied from a 30-13 fourth-quarter deficit to come within 30-29 with 51 seconds left at Oklahoma. Playing without injured star quarterback Trevone Boykin, TCU nevertheless was on the brink of victory pending a two-point conversion attempt.

Rolling out, backup QB Bram Kohlhausen found a wide-open receiver in the back of the end zone, but his lofted pass was slammed to the turf by a leaping Steven Parker, preserving the Sooners' victory and their place in the four-team playoff.

6. (Oct. 12) Will Grier's failed drug test:

Behind first-year coach Jim McElwain and the play of redshirt freshman quarterback Will Grier, Florida had been the surprise story in the first half of the season. The Gators trounced Ole Miss -- the only team to defeat Alabama all season -- and rolled to a 6-0 start.

But then Grier failed a drug test, saying he took an over-the-counter supplement that was banned by the NCAA. He was suspended for one year and Florida's season unraveled. The Gators lost their first game later that week to LSU, and though they still managed to win the SEC East, their offense went into a tailspin, scoring just two touchdowns in the season's final three games (all losses).

5. (Oct. 24) Down goes Seth Russell:

With five minutes left in the game against Iowa State, Baylor QB Seth Russell was hit on a scramble. The play didn't look like much at the time, but a day later it turned out he had fractured a bone in his neck.

The Bears were 7-0 after beating Iowa State and were the favorite to win the Big 12 and claim a playoff spot. But after Russell went down (as did his backup Jared Stidham), Baylor lost three of its last four regular-season games.

4. (Nov. 14) Timely blitz dooms Stanford:

Trailing Oregon 35-23 entering the fourth quarter, Stanford mounted a late comeback despite two fumbles by quarterback Kevin Hogan that short-circuited two drives in the final seven minutes. Hogan got Stanford to within two points at 38-36 with 10 seconds left with a two-point conversion pending.

The Ducks decided to blitz, forcing a hurried Hogan throw that fell incomplete. The loss denied the Cardinal an unbeaten conference season and effectively knocked the Pac-12 out of the playoff race.

3. (Nov. 21) Defending champ loses at the gun:

Ohio State had played mostly uninspired all season, eking out wins when it should've been blowing teams away. But the defending champs were still 10-0 entering a home game against Michigan State, which was playing without starting QB Connor Cook.

But again Ohio State floundered, allowing Michigan State to tie the game late and then chew up the clock to set up a game-winning kick. Michael Geiger's 41-yard field goal as time expired stunned the crowd at the Horseshoe and denied the Buckeyes the Big Ten East title and a return trip to the playoff.

2. (Nov. 7) Arkansas converts fourth-and-forever:

The one play that doesn't involve any of the championship contenders might've held the most sway. Trailing Ole Miss 52-45 in overtime, Arkansas faced a fourth-and-25, with defeat imminent.

Yet the Hogs somehow converted a first down after a wild lateral sequence. They went on to score a touchdown and then a two-point conversion to beat the Rebels, 53-52. The loss denied Ole Miss the SEC West crown, handing it back to Alabama, and relieved the selection committee the decision to leave the Tide out of the playoff since they failed to win their own division.

1.  (Oct. 17) Miracle at the Big House:

With 10 seconds left in a game it has trailed the entire way, Michigan State had one last chance when it forced Michigan to punt. Facing a full-house rush, Wolverines punter Blake O'Neill panicked, first bobbling the snap and then fumbling the ball away.

Jalen Watts-Jackson scooped up the loose ball and dashed 40 yards for the score to cap Michigan State's improbable 27-23 win at the Big House. The miraculous finish allowed the Spartans to trump both Michigan and Ohio State to win the Big Ten East and a place in the four-team playoff.

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-- Samuel Chi is the managing editor of RealClearSports.com and proprietor of College Football Exchange. Follow him on Twitter at @ThePlayoffGuru.