ATLANTA — Top-ranked Louisiana State arrived with a hunch: 45 points would be enough to beat Oklahoma in a College Football Playoff semifinal on Saturday.

It took less than 30 minutes for L.S.U. to pass that magic number as the Tigers pummeled the No. 4 Sooners, 63-28, to earn a berth in next month’s national championship game against Clemson, which edged Ohio State in the other semifinal later on Saturday night.

“We came out here to put up points, and we put up more than we expected,” Ja’Marr Chase, a sophomore wide receiver, said on the field after the game.

Indeed.

That the Peach Bowl was the scene of an offensive outburst was of little surprise. The matchup — with the nation’s best offenses, the Heisman-worthy quarterbacks who could roll and run from a swarm of trouble, the tailbacks who could cut past defensive linemen, the receivers who treated the turf as more of a launchpad than a football field — promised plenty of points.