Updated

Louisville and coach Charlie Strong now know firsthand the growing pains that come with these youthful Cardinals.

Junior Will Stein threw for a career-high 349 yards and two touchdowns, but the Cardinals gave up five sacks and too many big plays in losing 24-17 to FIU on Friday night, never leading against the defending Sun Belt Conference champs.

Strong has a young team in his second season with 20 players making their collegiate debut in the season opener a week ago and seven Cardinals getting their first starts in that game.

The Cardinals (1-1) held the ball for more than 36 minutes and outgained FIU 446-293 in total offense. It wasn't enough to make up for a 71-yard interception return for a touchdown and T.Y. Hilton's two TD catches of 74 and 83 yards.

"It's going to be one of those rollercoaster years, and we understand that because of the youth that we have," Strong said. "We go into a tough situation next week down at Commonwealth and UK and right now UK's a better football team than us. ... It's so important. We have to learn from this game, and we have to learn from the mistakes that we made."

Strong had two of his starters out with center Mario Benavides and defensive end B.J. Butler missing their second straight games.

Winston Fraser put FIU (2-0) ahead to stay as he stepped in front of a pass by Stein and ran up the left sideline for the TD midway through the first quarter. Hilton had a school-record 201 yards receiving, and the Panthers finished with two turnovers in the win for a program that started playing football in 2002.

Panthers coach Mario Cristobal called it an awesome evening.

"To be able to come into the home of a BCS team, playing the way we did, overcome a little bit of adversity there at the end, getting out of tough situations, I've never been more proud of a group of football players as a player or as a coach than those guys right there in that locker room," Cristobal said.

Stein threw his second TD pass with 1:49 left, and Louisville tried the onside kick only to see FIU recover the ball. The Panthers couldn't pick up a first down to run out the clock and had to punt the ball back with 38 seconds left and 97 yards to go.

Facing fourth-and-1, Stein completed a pass to Scott Radcliff who fumbled and FIU recovered to clinch the upset.

Hilton, the do-it-all senior being promoted for the Heisman Trophy, didn't touch the ball on offense until early in the second quarter. Hilton only needed two quick catches, the first off a slant from Wesley Carroll on third-and-4 as the receiver easily beat defenders for a 74-yard touchdown and a 14-3 lead.

The receiver did it again on the next drive, this time on third-and-11. He got behind the defenders, caught the ball, and no one came close to him as he finished off an 83-yard TD catch putting the Panthers up 21-3 with 9:28 left in the second quarter.

"There are a lot of things we have to change," Louisville linebacker Dexter Heyman said.

Louisville cut down its turnovers from an opening win over Murray State, and the Cardinals couldn't match the quick-strike offense of FIU and Hilton as they bogged down near the end zone.

Sam Miller and Tourek Williams had two sacks apiece for FIU with Williams' two coming on the same drive late in the fourth as the Cardinals tried to rally.

Stein capped a drive with a TD pass to Josh Chichester, but the 6-foot-8 sophomore's left foot landed on the end line out of bounds before they settled for a 30-yard field goal from Chris Philpott to pull within 7-3. Strong put in freshman Teddy Bridgewater at quarterback for a series before going back to the 5-10 Stein.

The junior managed to drive Louisville 89 yards and tossed a 6-yard TD pass to Michaelee Harris just before halftime to pull the Cardinals within 21-10.

FIU led 24-10 in the fourth quarter when Louisville drove 80 yards downfield before bogging down with fourth-and-1 at the FIU 7. The Panthers stuffed Jeremiah Wright for a 4-yard loss to stop another Cardinals' drive short of the end zone.