SANTA CLARA, Calif. >> Clemson needed a big performance to unseat defending champion Alabama. The Tigers got plenty of them from start to finish.

Cornerback A.J. Terrell got it rolling with a 44-yard pick six on Tua Tagovailoa’s third pass of the game, Justyn Ross had a stunning display of acrobatic catches and Clemson’s defense shut down hopes of a Crimson Tide rally with three unlikely stops on downs in the second half of a 44-16 victory tonight to win its second national title in three seasons — both over powerhouse Alabama.

It was an unexpected ‘Bama beatdown by the Tigers (15-0), who showed poise, strength on the offensive line and speed on defense to manhandle Nick Saban’s Crimson Tide (14-1).

“We came in with the mindset that we were going to play on the balls of our feet and we were going to attack. And we did. We attacked the whole night,” coach Dabo Swinney said.

It began almost immediately as Terrell stepped in front of Tagovailoa’s throw and ran untouched into the end zone to put Alabama on its heels, down 7-0. It wouldn’t be the last big play surrendered by the Crimson Tide.

Clemson quarterback Trevor Lawrence hit Tee Higgins with a 62-yard pass on third-and-14 deep in Tiger territory and Travis Etienne followed with a 17-yard TD run through Alabama vaunted defense. Tagovailoa’s second interception in the first half, this one by Trayvon Mullen, led to another Clemson score and a 28-16 lead.

In the second half, the 6-foot-4 freshman Ross and the Tigers defense took over.

Ross, an Alabama native who spurned his home state school for Clemson, made several outstanding and timely grabs. He broke free for a 74-yard TD catch and run that put the Tigers ahead 37-16. On a third-and-12, Ross grabbed the ball with just his right hand for a 37-yard gain with the Tide desperate to regain possession.

Alabama was going nowhere against Clemson when it mattered most. Backup defensive tackle Nyles Pinckney stuffed Alabama holder Mac Jones on a fake field goal try that ended far short of its goal.

Clemson linebacker Tre Lamar and safety Tanner Muse stopped Tagovailoa a yard short on fourth-and-3 on Clemson’s 14. And with Alabama hoping for any sort of momentum swing, All-American defensive end Clelin Ferrell stopped Tagovailoa for a 7-yard loss on fourth down near the goal line.

By then, the Crimson Tide had little left to give.

Lawrence, a freshman, was supposed to be rattled by Alabama’s fearsome defensive front. Instead, he threw for 347 yards and three touchdowns, looking as calm and cool has he has since winning the job in late September. He was named the offensive player of the game.

“It’s been an awesome journey. It’s really unbelievable,” Lawrence said.

Ross finished with six catches for 153 yards and his game-changing touchdown.