Analysis | Inside the wild comeback that sent the 49ers to the Super Bowl

They all stood near midfield as the scoreboard above glowed yellow with an improbable final score: San Francisco 34, Detroit 31.

“They had us in the first half, not going to lie,” tight end George Kittle joked onstage. San Francisco had trailed the Lions, 24-7, at halftime, and the 17-point comeback was tied for the largest in NFC championship game history. In the locker room, no one gave a rah-rah speech. Shanahan and linebacker Fred Warner reminded the team a trip to the Super Bowl was at stake. The players understood they needed to change things fast.

“Obviously, we don’t like to play from behind,” left tackle Trent Williams said. “We’re a balanced offense, we pride ourselves on being balanced, and when you’re down multiple scores, it’s hard to stay balanced, especially with as well as they were running the ball. You start to get concerned [about the number of possessions you’re going to get].”

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To start the second half, San Francisco sparked its offense by feeding all-pro receiver Deebo Samuel. Even though the drive stalled out, kicker Jake Moody, who’d missed three of his past four field goals, hit a 43-yarder.

On the next Niners drive, after a critical fourth-down drop by Detroit receiver Josh Reynolds, Purdy got to the line of scrimmage and saw the Lions in a defense with only one deep safety.

After the snap, Purdy said, he saw the safety had “sort of stayed flat-footed” and hadn’t dropped deep into the middle of the field. The quarterback heaved a long ball, trusting Aiyuk to beat corner Kindle Vildor one-on-one. Vildor stayed in front of Aiyuk, but when Vildor dove for the ball, it smacked him in the face mask and popped up in the air — and somehow, despite the speed and chaos, Aiyuk kept his focus and grabbed the ball for a 51-yard gain.

“I don’t even know,” Aiyuk said.

Three plays later, Aiyuk caught a short post route for a touchdown. The 49ers had pulled within a touchdown.

The next drive, San Francisco expected Detroit to run. The Lions had gashed the 49ers all game with different concepts. No one understood the threat better than veteran safety Tashaun Gipson, who the quarter before had been juked badly on a touchdown run by running back Jahmyr Gibbs.

It was hard to stop the Lions’ rushing attack, Gipson said, because they have one of the NFL’s best offensive lines, a diverse scheme, an excellent play caller and “thunder and lightning” complements in the backfield. So San Francisco countered by playing an aggressive, man-to-man defense. Gipson was assigned to a tight end, but when he saw quarterback Jared Goff hand the ball to Gibbs, he broke inside. Gipson met Gibbs near the line of scrimmage, and when Gibbs tried to spin away, Gipson reached his right arm and ripped the ball out. San Francisco recovered the fumble; Levi’s Stadium exploded.

Several 49ers said the fumble was the biggest play of the game. Even though they still trailed, 24-17, it was the moment they knew they would pull off the comeback.

“You can feel it in the air,” right tackle Colton McKivitz said. “You can feel it on the field. You can feel the guys’ body language. [The Lions had] a lot of talk early. They came in pretty chippy. Just couldn’t handle the second half.”

Over the final 20 minutes, San Francisco squeezed Detroit like a boa constrictor. Running back Christian McCaffrey pounded away against heavy boxes. Purdy, who had never run for a gain of 20 yards in his NFL career, scrambled for more than 20 yards twice. Reynolds had another drive-killing drop, and Detroit failed on another fourth down. San Francisco took a final knee.

Quickly, stadium staffers wheeled out black funnels strapped to canisters of carbon dioxide. They shot the red-and-gold scraps of paper into the air, and as the 49ers celebrated, Lions Coach Dan Campbell and his players told reporters things like: this “sucks,” “pretty devastated” and “it’s like getting your heart ripped out.”

On the field, kids made confetti snow angles. Old stars ambled around, congratulating new ones. Richard Sherman ran over to Niners defensive end Nick Bosa and his family, screaming, “See you in Vegas!” Shanahan said to his family, “You ready to party?” which earned him cheers.

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The locker room air was thick with cigar smoke. Players rehashed the game with teammates and family members. Receiver Jauan Jennings belted out a song by the rapper Gunna on Instagram Live. One 49ers staffer joked that the Lions’ coach might be upset enough to “bite kneecaps,” a reference to Campbell’s fiery opening news conference.

One of the last players in the locker room was Williams. This is his 14th NFL season, and soon, he will play in his first Super Bowl. He seemed to feel reflective and readily admitted the 49ers couldn’t have pulled off the comeback without a few good bounces.

“It’s football,” he said. “Nobody wins without a little luck. … They dropped some big balls that were wide open and could’ve kept drives going. We missed a field goal [early but then came back].”

“There’s a little luck involved in all of this, man,” he added. “It’s just our time to get it.”