Miami ? In the end, Mark Bradley’s blunder didn’t decide the Orange Bowl. It merely triggered the scoring onslaught that helped Southern California drub Oklahoma.

Bradley’s ill-advised punt return proved disastrous for the Sooners when he fumbled the ball away Tuesday, setting up the touchdown that put the Trojans ahead to stay en route to their 55-19 victory for the national title.

“That was just a bonehead play,” Bradley said. “I don’t know what I was thinking. It really turned the momentum of the game.”

It was the first of five turnovers by Oklahoma, and the most costly. Barely five minutes later, USC had turned a 7-all game into a 28-7 lead.

The play began with a poor punt by USC’s Tom Malone, but the ball took a favorable bounce for the Trojans inside the 10 as returner Antonio Perkins wisely got out of the way.

Then Bradley entered the picture. A big-play receiver and the son of Danny Bradley, a quarterback for Oklahoma in the 1985 Orange Bowl, the Sooners’ senior was an unlikely candidate to become a goat.

But Bradley tried to block a USC player, and with the ball about to roll dead he inexplicably scooped it up, even though he was surrounded by Trojans. One of them, Collin Ashton, quickly knocked the ball loose, and it was recovered at the 6 by Josh Pinkard, a true freshman and fourth-string safety.

“I have no idea why Mark would have done that,” Oklahoma coach Bob Stoops said. “I was as shocked as anybody in the stadium.

“It’s as bad a play as there is.”

Bradley, appearing dazed by what he had done, walked to the bench and was consoled by teammates. Officials threw a flag on the play but huddled, then decided that there was no penalty — and that USC had not touched the ball before Bradley reached it, despite protests by Stoops.

“Mistakes can kill, and that was a big mistake,” Trojans defensive end Lawrence Jackson said. “In a big game, he thought he could get something going.”

LenDale White scored on the next play to give USC a 14-7 lead, and the rout was on. By halftime, USC was ahead by 28 points.

“It’s part of life, and part of the game,” Bradley said. “You have to accept it and learn from your mistakes.”