There’s a fine line between swagger and cockiness. The early-season 49ers seemed to lean a little too close to the latter. Sunday was a show of the former.

In a 34-3 bludgeoning of the Jacksonville Jaguars, San Francisco reclaimed its identity, rubbing a little salt into the wound. They sacked Trevor Lawrence five times, forcing two interceptions and strip-sacking him once.

Fred Warner was ruthless after the game when reminiscing on his late interception that put the nail in the coffin.

“Trevor Lawrence, he throws a good ball, came with a nice spiral to me,” Warner said, chuckling. “That’s my bad, I shouldn’t have said that.”

Kyle Shanahan did something a little similar at the end of the game.

With a 34-3 lead, and a goal-to-go situation, he injected Christian McCaffrey back into the game to try and get him sole possession of the NFL record for consecutive games with a touchdown (he had 17-straight games, which tied him for the record). Shanahan gave McCaffrey four-straight touches and failed to get him in, but it was a clear edict to get his guy the record, much like his father worked to get Terrell Davis a 2,000-yard rushing season.

He went up to Doug Pederson after the game to clear the air, but you couldn’t really blame Pederson if he was bothered by it.

That’s the 49ers when they’re rolling. They’re physical, athletic, schematically exhausting, intelligent and confident.

It’s how they felt at the start of this season, on a 5-0 roll where they let their egos get overblown and lost the plot on a three-game skid. But they got their confidence back Sunday in a way that draws the mind immediately to this classic:

For the first time since they were humbled in that last-second loss in Cleveland, they were led out of the tunnel by Trent Williams and Deebo Samuel, with their iconic Bumpboxx speaker in tow.

Chase Young got right into the mix.

His acquisition was a clear statement from the front office about where it believes this team is headed, and it’s evident that he’s fitting in. The fact that he and Nick Bosa sacked Trevor Lawrence simultaneously for a strip sack that Bosa stole was something out of Ohio State fan fiction.

That defensive line has been the crux of the 49ers’ identity since Shanahan arrived. After failing to get home for weeks, they made Lawrence run for his life until former 49er C.J. Beathard relieved him late in the fourth quarter.

It felt like there was a tangible vibe shift. Something came out of the bye week, and the decision to bring Steve Wilks out of the booth to the sideline has to be seen as substantial.

Coaches downplayed that impact. Wilks said this week more was being made out of it than should be the case. Shanahan said after that game “… I think that’s one of the most overrated things in the world.

Still, he said he enjoyed having Wilks on the sideline.

Shanahan is right that it’s probably overblown. But that distance from the press box looms large when things aren’t going well.

Wilks was, and to some extent, still is an outsider. Robert Saleh and DeMeco Ryans were young, physical presences on the sideline. They’d seen Fred Warner’s growth from pup to franchise lynchpin. Wilks wasn’t there for that.

He had to re-establish trust. Having him on the sidelines with his players creates a level of connectivity and added communication that’s not worth shrugging off. You’re not going to talk behind your coordinator’s back when you’re literally behind his back. At least, you shouldn’t.

And if the decision didn’t mean anything, Shanahan and Wilks wouldn’t have made it.

His players clearly appreciated the shift.

“I felt his energy,” Arik Armstead said. “He came up to us, congratulated us on some plays, that voice that’s telling us to keep going. Yeah, I definitely felt him on the sideline.”

Warner echoed that.

“It was good,” Warner said. “It was good having him down there. The communication was was flawless.”

Now, there are still causes for concern with this defense. They got diced up on screens over an extended stretch, once again showing vulnerabilities at their edges and their ability to contain on the outside.

The Jaguars drove the ball deep into 49ers territory. Those possessions ended on turnovers, which aren’t a reliable way to get stops. Deommodore Lenoir looked out of sorts at times, and Charvarius Ward is still good for a holding call or two a game.

The back end has work to do.

But the speed and energy that Shanahan said was missing against Cincinnati was back. The pass rush had teeth. More than anything, their confidence was back. A midseason exercise in humility taught them how valuable that is. It’s hard to imagine they’ll forget that lesson.