Who’s No. 1? How about USC.

A week before Florida and Oklahoma meet in the BCS title game, No. 5 Southern California played like a champion in the 95th Rose Bowl, defeating No. 6 Penn State 38-24 on Thursday in a game not nearly as close as the final score might indicate.

Mark Sanchez passed for a career-high 413 yards and four touchdowns, and the Trojans raced to a 31-7 lead by scoring four TDs and a field goal on their final five possessions of the first half against a defense that allowed an average of 12.4 points during the regular season.

‘‘We executed well and we knew we were going to have to play well in a big-time game,’’ Sanchez said. ‘‘I think we really maximized our potential. It was something special to be a part of.’’

The Nittany Lions scored 17 points in the fourth quarter to make the final score respectable.

One loss was all it took to bounce the Trojans out of the BCS championship race — a 27-21 setback Sept. 25 at Oregon State. The Beavers lost at Penn State 45-14 three weeks earlier.

USC (12-1) can only wonder what might have been had it gotten to play next Thursday night in Miami. The Trojans finished the regular season ranked fifth behind four one-loss teams — Florida, Oklahoma, Texas and Alabama.

The Trojans won 10 straight after losing to Oregon State, outscoring the opposition 380-80. That wasn’t enough to sway the voters.