Perspective | These 49ers have shaped the NFL. Now it’s time to cement their legacy.

It’s a challenge that keeps threatening to suffocate these 49ers. But they’re still breathing, seeking that rarefied air.

On Sunday night, San Francisco clinched its second Super Bowl appearance in five seasons, exerting all that it had to capture a historic 34-31 comeback victory over the Detroit Lions in the NFC championship game. The Niners fell behind 24-7 at halftime. Twenty-one teams had faced title game halftime deficits of at least 17 points, and all of them had lost. But the 49ers chose to make history. They put everything they’ve spent five seasons building on the line, knowing that an embarrassing defeat could trigger significant change. Somehow, all that weight suddenly felt light.

“We’ve never been a part of nothing like that,” safety Tashaun Gipson Sr. said. “Why not do something great?”

San Francisco has a mantra, one that Coach Kyle Shanahan borrowed from Dan Quinn when they worked together in Atlanta: “Do right longer.” It’s about mindfulness, task persistence, the will to play clean football even while understanding the impossibility of perfection. It’s a competitive summons that has helped the 49ers through the injuries and difficult defeats along the winding journey to win a first Super Bowl since 1995. And on this night, persistence was the only way to combat the Lions, who attacked this game early with a rugged yet carefree vigor.

They ran over and around the San Francisco defense, amassing 148 rushing yards and averaging seven yards per carry in the first two quarters. On their opening drive, wide receiver Jameson Williams burst into the end zone for a 42-yard score on an end-around run. David Montgomery, Detroit’s power running back, rumbled. Jahmyr Gibbs, who runs like electricity courses through his legs, dazzled. Quarterback Jared Goff leveraged the ground game brilliantly for easy completions to open receivers. The offense fooled a well-regarded defense, and the 49ers couldn’t keep up when they had the ball. Their second-year quarterback, Brock Purdy, completed only 7 of 15 passes and threw an interception during the first half.

“It was exactly what we didn’t want to happen,” San Francisco linebacker Fred Warner said of the start.

When you’re doing almost nothing right, can you still strive to do right longer? It’s the perfect nagging question for the 49ers. In the past five seasons, they’ve posted a 54-29 record. They’ve won at least 12 games, the standard for regular season dominance, three times. They’ve made the playoffs four times, won two games in each of those postseasons and advanced to the NFC title game on every occasion. Shanahan has a splendid 8-3 playoff record, and now he’s headed to his second Super Bowl, where the 49ers will face Kansas City in a rematch of the Chiefs’ 31-20 triumph in Miami four years ago.

It’s an extraordinary amount of success for a team that has yet to be fitted for rings. The 49ers are part of a trio of teams experiencing the cruelty of consistent but insufficient winning. The Buffalo Bills have gone 58-24 the past five years and flashed their championship potential numerous times, but they’ve made it as far as the AFC championship game once. The Baltimore Ravens, fresh off a 17-10 loss to the Chiefs, are 56-27 and earned the AFC’s No. 1 seed twice during that same span. They’re still in pursuit of their first Super Bowl appearance with Lamar Jackson.

The 49ers, Bills and Ravens have one common nuisance: Patrick Mahomes and the Chiefs. A Kansas City team approaching all-time greatness has turned back all three at least once. The Bills have been repeatedly tormented. Still, despite Kansas City’s dominance, there has been room to thrive around the Chiefs’ two Super Bowl victories. But these prime contenders have done much to narrow their championship windows.

San Francisco may be down to its last chance to win with all the essential core stars on this team. The 49ers should be good for much longer, but their days of regularly featuring a half dozen all-pros are almost over. As they’ve strained through home victories over Green Bay and Detroit to reach the Super Bowl, you’ve seen the margins tighten on this team. But the 49ers still aspire to do right longer.

On Sunday, they scored 27 unanswered points to eliminate that 24-7 deficit before holding off Detroit’s effort to rally. Purdy wound up with 267 passing yards and 48 yards on scrambles that Shanahan thought were “the difference between winning and losing.” The defense held up despite allowing 442 yards to Detroit. The Lions ran just eight times for 34 yards in the second half.

Detroit, always ultra-aggressive, also declined to try field goals in the third and fourth quarters, twice attempting fourth-down conversions that failed. The final try came on an incomplete Goff pass midway through the fourth quarter. Detroit was trailing 27-24 at the time. Instead of kicking what would’ve been a 48-yard field goal. Coach Dan Campbell stayed true to his ways.

In this case, it was a stubborn decision with his team floundering. The Lions weren’t executing well enough to believe they could get those three yards.

“I don’t regret those decisions,” Campbell said afterward. “And that’s hard. It’s hard because we didn’t come through. It wasn’t able to work out. But I don’t. And I understand the scrutiny I’ll get. That’s part of the gig, man.”

In his rawest moment, Campbell admitted the difficulty of getting a chance at redemption. With a young team that just experienced its first playoff adventure, the Lions should be contenders for a while. But nothing is promised, and Campbell isn’t afraid to acknowledge that.

“I told those guys this may have been our only shot,” Campbell said. “Do I think that? No. Do I believe that? No. But I know how hard it is to get here. I’m well aware. And it’s gonna be twice as hard to get back to this point next year than it was this year. That’s the reality.”

That’s the reality the 49ers have faced and outlasted for five years. They’ve learned to ignore the clock and to keep demanding the best of themselves.

Gipson, who forced a key Gibbs fumble during San Francisco’s surge, can admit to worrying now. He had lost an AFC title game while in Jacksonville before losing an NFC title game last season with the 49ers. Down 17, he wondered if the game was torturing him again.

“I just sat there, and I looked, and it was like, this will be my third time in 12 years getting this close,” he said. “I’d be lying to you if I said doubt didn’t creep in. I’m human. Just being that close three times, it was unsettling.”

Gipson and his teammates can relax. They’re headed to Las Vegas.

“One more game to cement to all of our legacies,” Gipson said.

One game to advance from influencers to legends.