GLENDALE, Ariz. — In the biggest upset since the advent of the College Football Playoff, third-seeded TCU rode its underdog status to a 51-45 win over undefeated and No. 2 Michigan in the Fiesta Bowl on Saturday. The win continued TCU’s storybook season and made the Frogs the first Big 12 team to reach the title game in the CFP era.

Highlighted by a 44-point third quarter between the two teams, the semifinal matchup was a back-and-forth affair that saw TCU nearly lose an early 18-point lead, a pair of pick-sixes, two fumbles, a 76-yard touchdown pass, eight scores in just about eight minutes, a record-setting 59-yard field goal and the highest combined score in Fiesta Bowl history.

The signs of an explosive game were there early. Starting in place of injured star running back Blake Corum, Donovan Edwards ripped off a 54-yard run on the first play of the game, yet the Wolverines walked away with zero points after a fourth-down try near the red zone was stopped.

On the next Michigan offensive drive, quarterback J.J. McCarthy threw a telegraphed pass to the outside that was picked off by sophomore safety Bud Clark and returned for a touchdown. It was the Frogs’ third pick-six of the season and put them up 7-0.

The Frogs’ defense was the star of the first half, as Michigan entered the TCU red zone three times and came away with only nine points by way of three field goals thanks to two huge stops and a fumble at the 1-yard line by Edwards.

TCU’s offense, meanwhile, used the advantage of the Air Raid’s pace and speed to get out in front. A 12-play, 76-yard drive culminated with quarterback Max Duggan rushing into the end zone from the 1-yard line to put the Frogs up 14-0 in the first quarter. Under coach Jim Harbaugh, Michigan had allowed more than 14 points in the first quarter and gone on to win just once, in 2016 against Colorado, according to ESPN Stats & Information research.

While Michigan struggled to capitalize, on the other side of the ball, Duggan — the Heisman runner-up — was pulling out all the stops. Duggan wasn’t particularly accurate through the air in the first half, but with his legs, he danced his way to first downs and kept pushing TCU downfield as the Wolverines struggled to mitigate his mobility.

No play was more indicative of that problem than when Duggan rolled out of the pocket with 4:56 left in the second quarter and avoided the Michigan blitz to find Taye Barber for 6 yards and six more points. The touchdown culminated a 10-play, 83-yard drive that gave the Frogs a commanding 21-6 halftime lead and put the Wolverines in their biggest deficit of the season.

Both teams came out of the tunnels after halftime like they were shot out of a cannon, combining for a 44-point third quarter that featured a flea-flicker touchdown from McCarthy, the second pick-six of the game from the Michigan quarterback, another pick from Duggan and three touchdown drives of under three minutes.

McCarthy and Michigan, who had two of those drives, were not going away. But just as the Wolverines were attempting to claw back, TCU kept responding. This time, it was running back Emari Demercado who broke loose for a 69-yard run that Duggan finished off with another 1-yard touchdown sneak. The Frogs finished with 41 points through three quarters. All season, the most points Michigan had given up in an entire game was 27, and going back to last season, the most the Wolverines had surrendered in a game was 37.

After Michigan cut the TCU lead to three points early in the fourth quarter, Duggan, as he has done all season, responded by making the throw of the game. While facing a blitzing defender in his face and a long third down, Duggan found a crossing Quentin Johnston in stride. Johnston sped his way to the sideline and took it 76 yards to the end zone to put the Frogs back up 10. A field goal extended that lead to 13 early in the fourth quarter.

Another methodical Michigan touchdown drive by McCarthy cut the lead once again, this time to six points with 3:18 left, setting the stage for TCU and Duggan. The Frogs needed two first downs to finish the game with the ball in their hands. They could get only one, and the Wolverines had 52 seconds to go 75 yards and make a miracle happen.

On fourth-and-10 with 35 seconds left at its own 25, Michigan fumbled the ball and recovered, but the ball did not make it past the first-down marker. As TCU assistant coaches in the upstairs box yelled and screamed, “We’re going to the Natty!” all Duggan had to do was take a knee. The upset of the season — and of the era — was complete.