By Mark Gallagher 

LSU capped a magical season with a 42-25 victory over Clemson to win the national championship at the Louisiana Superdome.

The Tigers did it largely by riding Joe Burrow, who won the Heisman Trophy last month, using his precise right arm, his nimble legs and his keen football mind to thwart a determined Clemson defense that had been the toughest to score against in the nation this season.

Clemson battered Burrow, sacking him five times, but he nevertheless torched the opposing defenders for 463 yards passing and five touchdowns, running in another as LSU rallied from an early 10-point deficit. He celebrated afterward — like a number of his teammates — with a cigar.

And why not? The victory, which snapped Clemson’s winning streak at 29 games, capped one of the most rigorous unbeaten runs any team has ever made. L.S.U. beat six teams that were among the top 13 in the final regular-season College Football Playoff rankings.