ATLANTA (AP) — Jeff Brohm's coaching debut at his alma mater wasn't nearly as smooth as he would've liked.

That's OK.

Louisville found a way to win after falling behind by 15 points at halftime.

Transfer quarterback Jack Plummer rallied his new team with three touchdown passes, Dezmond Tell made a huge defensive play and the Cardinals knocked off Georgia Tech 39-34 Friday night.

“We have a long ways to go,” said Brohm, who returned to Louisville after coaching the last six years at Purdue. “But like I told ‘em, every college football game is gonna be like that. If you’re not ready for that, you might as well not show up for the game.”

Plummer hooked up with Jamari Thrash on a 20-yard scoring play with 8:08 remaining to put the Cardinals ahead at Mercedes-Benz Stadium, home of the NFL’s Atlanta Falcons and about two miles from the Georgia Tech campus.

Louisville sealed the opener between Atlantic Coast Conference rivals when Tell blindsided new Georgia Tech quarterback Haynes King, forcing a fumble that thwarted a potential go-ahead drive.

Jawhar Jordan broke off a 74-yard touchdown run on the very next play. Louisville outscored the Yellow Jackets 26-6 in the second half.

“I challenged the guys at halftime to play much harder, much tougher, just figure out a way to grind this thing out,” Brohm said.

It was a tough setback for Brent Key, beginning his first full season as Georgia Tech’s coach. His team erupted for four touchdowns in the second quarter and a 28-13 lead at halftime, but they couldn’t get anything going in the second half.

“You only get 12 chances a year at these opportunities,” Key said. “You've got to be able to sustain for the entire game.”

Plummer, who transferred to Louisville to reunite with Brohm after three seasons at Purdue and one year at Cal, completed 18 of 31 passes for 247 yards with one interception.

King, a former starter at Texas A&M, threw for 313 yards and three touchdowns, while former Louisville running back Trey Cooley added a pair of TD runs against his old school.

But King was kicking himself for a pair of interceptions, including a deflected pick on his first pass of the game, not to mention that back-breaking fumble.

“You can't hold onto the ball there,” King said. “That's a mental error by me.”

Key took over as interim coach last season after a 1-3 start ended the dismal tenure of Geoff Collins. Key posted a 4-4 mark the rest of the way and was rewarded with the full-time job.

In his first game with the permanent title, the Yellow Jackets scored their most points in a quarter against a top-division opponent since 2014.

It wasn't enough.

Georgia Tech had touchdowns on four straight possessions, beginning with King's 2-yard touchdown pass to Brett Seither. Cooley scored on runs of 1 and 23 yards before King's short toss to Chase Lane resulted in a 48-yard TD.

Louisville: Plummer looked downright shaky in the first half, and even more so when he missed a wide-open receiver in the end zone early in the third to force another field goal in the red zone. But he was 10 of 14 for 157 yards over the final two periods. “It was not his best first half, without question,” Brohm said. “He was misfiring. He was timid. He was not cutting it loose.” In the second half, “we ran the ball, got him some easier completions, and he got in a better rhythm.”

Georgia Tech: Key talks boldly of turning the Yellow Jackets into a championship contender, but they're still a long way from being a four-quarter team. They squandered a prime opportunity to go above .500 for the first time since a season-opening victory over Florida State in 2020.

Thrash had plenty of fans cheering him on.

A native of LaGrange, about an hour's drive southwest of Atlanta, he played the last three years at nearby Georgia State.

In his Louisville debut, Thrash finished with seven catches for 88 yards and two TDs.

“It's pretty cool coming back home, playing in front of your hometown,” he said. “I just wanted to make sure we got the win.”

Louisville: Hosts another Kentucky school, Murray State of the FCS Ohio Valley Conference, in the home opener Thursday night.

Georgia Tech: Returns to campus to face FCS school South Carolina State of the Mid-Eastern Athletic Conference next Saturday at Bobby Dodd Stadium.