PITTSBURGH — Upon his promotion to interim head coach Monday, Georgia Tech’s Brent Key had a message for his rattled team that had just lost its head coach – stop playing not to lose and instead play to win.

Yellow Jackets players, sick of losing and frustrated by their hand they had played in it, listened and responded.

In what rates as an all-time upset in school history, the Jackets shocked No. 24 Pittsburgh 26-21 on Saturday night as 22-point underdogs. In its first game since the Monday firing of coach Geoff Collins, the Jackets produced a series of game-changing plays to end their nine-game losing streak against FBS opponents, the past five of which had been lost by a combined 217-20.

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“I’m so happy for these kids,” Key said. “I believed in them. I knew they had it in them.”

Given a 9.4% chance of winning by ESPN metrics, Tech (2-3, 1-1 ACC) had contributions from the offense, defense and special teams. Kicker Gavin Stewart, elevated ahead of Jude Kelley, made all four of his field-goal attempts, including a 40-yarder in the third quarter that gave the Jackets a 9-7 lead that they held for the remainder of the game.

Linebacker Charlie Thomas, entering the game in the second half after serving a targeting suspension, returned a fumble 43 yards caused by safety Jaylon King that set up Stewart’s go-ahead field goal. He thwarted another Pitt possession with an interception later in the quarter that led to another field goal.

“I just wanted to play for my guys,” said Thomas, who was all over the field in the second half withseven tackles, an interception, a quarterback hurry and the fumble recovery. “They were playing for me the first half, so I just wanted to show them I was going to do the same for them in the second half. I just appreciate them. I love my teammates. I just felt like we were playing for each other out there.”

The offensive line, against a Pitt defense that had allowed 98.5 rushing yards per game in its first four games, led the way for 232 rushing yards. Running back Hassan Hall, given his first start of the season, ran fast and tough for 157 yards after having gained 103 in the team’s first four games. He tore off a 63-yard run after Pitt (3-2, 0-1) had closed the score to 19-14 with 1:55 remaining that set up quarterback Jeff Sims’ 18-yard TD run with 1:25 left that lifted the Jackets’ lead to 26-14.

The punting unit, changed up by newly appointed special-teams coordinator Jason Semore, allowed punter David Shanahan to safely punt six times with no blocks after having given up four blocked punts in the first four games this season.

“Obviously, that was a big thing this week putting that punt team together,” Key said. “I credit Jason Semore for the work he did during the week of getting those guys ready to go.”

Tech’s defense generated three turnovers and a fourth-down stop. Linebacker Ayinde Eley led with 14 tackles, 2.5 for loss.

Georgia Tech 26, Pittsburgh 21

It was a remarkable turnaround for a team that had made been thoroughly outplayed in its three losses this season, play that led to the dismissal of Collins at the start of his fourth season. In less than a week, Key has effected a stunning change in the team, evident not only in superficial measures like putting away the “Money Down” signs and releasing a depth chart instead of Collins’ “Above the Line” chart, but helping the team to play fast on defense, Sims to run with abandon not seen this season and settling the shaky special-teams unit.

“We focused on working this week, not playing around and not doing anything that’s not going to help us win, just staying focused in practice and go out there and give it all we’ve got like we’re in a game,” Sims said.

As Key had sought, the Jackets played fast and with toughness. They limited penalties. They got a bit lucky, exhibited mostly in at least four throws by Sims that could have easily been intercepted. But they took advantages of their opportunities, too, such as Sims’ 21-yard floater of a touchdown pass to receiver E.J. Jenkins in the fourth quarter that lifted the Jackets’ advantage to 19-7.

“Just counting that as blessings,” Sims said of his near misses. “Obviously, I had a few passes that could have been bad. I just got to forget about it and move on to the next play and just do everything I can to help the team win.”

The game was played in an intermittent rain, remnants of Hurricane Ian. An unsurprisingly sparse crowd ventured to the stadium formerly known as Heinz Field.

Just after 8 p.m., Key gathered the team in the southwest portal and led them onto the field in a light jog, a laminated play sheet in his hand. During pregame warmups, Key said he wasn’t sure how to act or where to go. Normally, as offensive line coach, his responsibility was to get the offenisve line ready. Saturday, the expectations were unknown to him.

“I’m, like, walking around with a whistle hanging around my neck going, ‘What the heck am I doing with this thing?’ I didn’t know what to do,” he said. “I think it (quarterbacks coach Chris Weinke) was like, ‘Just walk around and act like the head coach.’”

He said he soon fell into the rhythm of the game after the game began. Tech won the toss and elected to receive, an aggressive maneuver. The strategy was rewarded when the Jackets drove for a 37-yard field goal by Stewart after Sims was almost intercepted on the first play of the game that appeared that it could have been returned for a touchdown.

It was the first time that Tech had scored on its first possession of the game since doing so against Boston College last year in the 10th game of the season. It was the Jackets’ first lead against an FBS opponent since that game, too. It was the first of many successes Saturday night.

“It’s a great feeling,” said linebacker Ayinde Eley, who caused a fourth-quarter fumble that set up the offense for a short field and Gavin Stewart’s fourth field goal of the game. “It’s one of those feelings youc an’t really describe. Just going out there with your brothers and winning a football game. It sounds simple but it means a lot to a lot of people in that locker room. It just feels good when you can come back and see everyone smiling and joyful. It’s a great feeling.”