LOUISVILLE, Ky. (AP) — Bobby Petrino was glad to see Louisville pile up points the way he envisioned.

Having underclassmen contribute to the team-wide effort against Murray State made the first-year Cardinals coach feel even better.

Leading the way was freshman backup quarterback Reggie Bonnafon, who ran for two touchdowns and passed for another as the No. 25 Cardinals scored on nine straight possessions in a 66-21 victory over the Racers on Saturday night.

"I have been putting in work at practice for a while and to finally come out here and see it pay off felt great," Bonnafon said after completing 8 of 11 passes for 112 yards and a 27-yard touchdown to Michaelee Harris. He also ran for touchdowns of 8 and 16 yards.

Bonnafon wasn't the only youngster who thrived.

Sophomore Brandon Radcliff rushed for 97 yards and second-half TDs of 7 and 5 yards, and freshman L.J. Scott ran for a game-high 126 yards and a 1-yard TD on 11 carries. Louisville rushed for 325 yards, 33 more than Murray State gained on offense.

Besides Bonnafon's two TDs, three other Louisville backs rushed for scores. Three receivers caught TD passes from the true freshman and sophomore starter Will Gardner, who threw two in just over a quarter of action. The Cardinals had 357 yards at halftime, 21 more than they totaled in Monday night's 31-13 victory over Miami as they outgained the FCS-level Racers (1-1) 603-292.

Senior Dominique Brown added a 2-yard TD run before Louisville's underclassmen picked up where he left off.

The result was a high-octane offensive performance that delighted 50,179 red-clad Cardinals fans and Petrino, who insisted that his team would improve from its performance against Miami. The short week didn't the bother the Cardinals, who showed energy throughout on both sides of the ball.

Having a lot of bodies available helped.

"We really showed maturity as a team," Petrino said. "These games are sometimes hard to play, especially coming off a game like Miami where we had so much time to prepare and it was so intense. But we showed maturity and we did a nice job preparing for it, and they came out and executed well."

Janawski Davis had TD receptions of 57 and 9 yards, and Jeremy Harness had a 16-yarder for Murray State, which was outmatched in every phase by the Cardinals just a week after thumping NAIA Union College 73-26.

"At the point of attack, that's where we were hurt early in the game," Racers coach Chris Hatcher said. "I mean, golly, they were so big and physical we couldn't run the football versus a five-man box. When you can't do that you're going to have a lot of trouble. ...

"We played an opponent that was better than us. They took care of business like they should have."

So much so that Bonnafon almost stole the spotlight in his first game action. He had pushed hard for the starting job before Petrino chose the more-experienced Gardner to lead Louisville's offense.

Gardner appeared much smoother than Monday, completing 13 of 22 for 133 yards and touchdown passes of 12 yards to Kai De La Cruz and 1 yard to Gerald Christian before Bonnafon followed. More importantly, he set the tone for an offense that kept rolling after his departure.

"He seemed much more confident out there," Petrino said of Gardner. "He was relaxed. He really understood what we were asking him to do."

Gardner's better understanding helped get Louisville started toward its big night.

After that initial punt, Louisville scored on its last seven first-half possessions with an 11-play, 32-yard march ending with John Wallace's 45-yard field goal being the longest snap-wise. By then the Cardinals were up 42-7 behind two touchdown passes from Gardner, a 2-yard run by Brown and contributions from Bonnafon and Scott.

Scott's effort was helpful in creating backfield depth after Brown had career bests of 33 carries for 143 yards against Miami. With just four days to prepare, he figured he'd see action.

"During the week they had let me know, 'Scott be ready, Scott be ready,' " Scott said, "so come game time when they called my number I really wasn't surprised and I wasn't really nervous."