For better and occasionally worse, Jaylen Brown has always played like he’s certain he can beat any opponent who dares set a sole on the parquet.

In every game recently, no matter the court or competition, Brown has played with a relentlessness and focus that is making even his skeptics — a camp I’ve occasionally joined — believe in him the way he’s always believed in himself.

The Celtics’ 27-year-old wing — who somehow is already in his eighth season as a Celtic, or as many as Danny Ainge and Cedric Maxwell played here and one more than Dennis Johnson — is in the midst of his most efficient and effective season of his career.

Brown is shooting a career-best 50.3 percent from the field. His 3-point percentage (35.7) isn’t going to earn him Honorary Curry status, but it is up from 33.5 percent last year. And he’s being more selective from long range — his attempts are down from 7.3 to 5.9 per game. His effective field goal percentage (56.1) is also the best of his career.

He’s been on an otherworldly heater since the All-Star break — in fact, he’s never been better. In 11 games since his noble quest to make sure that the Dunk Contest included at least one legitimate NBA player, Brown has averaged 29.1 points. 6.1 rebounds, 3.5 assists, and 1.2 steals per game, shot 54.1 percent from the field and 41.3 percent from 3, while committing just 1.5 turnovers per game and averaging a plus/minus of plus-15.5 per game.

Sure, his scoring average overall is down, from 26.6 points per game last year to 23.3 this season, but that’s a good thing. He’s acclimated to playing with Kristaps Porzingis in a way I wasn’t sure was viable. Would there be enough shots to go around after Jayson Tatum took his portion?

It turns out that Brown and Porzingis have had impeccable chemistry from practically the season’s opening tip. That’s a tribute to both of them, but particularly to the guy who was already established here.

(I also suspect that playing with Jrue Holiday and Derrick White — who have continued the Celtics tradition of excellent, wholly unselfish, players — has rubbed off on everyone.)

For all of the impressive stats — which included 31 points in 30 minutes in Monday night’s wipeout of the Pistons — so much of Brown’s progress is visceral. He’s playing with such a tone-setting edge, a you-cannot-stop-me intensity, and he is one mean dunker. Brown threw the ball down so hard in Grayson Allen’s mug late in the recent win over the Suns that that the dastardly Allen didn’t even have time to concoct a way to cheap shot him.

Brown knows he can overpower most defenders, and he takes delight in doing so. Basketball-reference.com lists him at 223 pounds. So does Celtics.com. He says he’s around 240 pounds now, and it’s obviously all muscle. He actually looks leaner in some ways than he did as a freshman at Cal.

His hard work is as evident in his skill as it is his strength. That 14-foot turnaround jumper, close to automatic these days, is the product of repetition. He’s vastly improved his handle (I think he offloaded that odd athletic awkwardness to Oshae Brissett, who careens), and makes quicker and better decisions.

Defensively, he’s more consistently committed than ever, often at his best when he has the toughest matchup. And mind games don’t seem to rattle him anymore, as Draymond Green found out a few weeks back when Brown rained 3s all over Green’s silly scheme to let him shoot.

It’s funny: Players are often accused of getting comfortable after landing a life-altering contract, as Brown did this offseason when the Celtics signed him to a $304 million supermax extension. But Brown has gotten comfortable in a different way, the right way, like the new deal is both validating and freeing, allowing him to become the best version of himself on the court.

Brown has actually received votes for Most Improved Player three times in his career: He was seventh in 2018 (when Victor Oladipo won it), 11th in 2020 (Brandon Ingram), and tied for sixth with Toronto’s Chris Boucher in 2021 (Julius Randle). Brown was second-team All-NBA last year, and yet his growth from last season to this one to me is the biggest leap forward of his career.

There’s still room for more growth, of course. Brown is shooting a career-worst 70.5 percent from the free-throw line, with almost all of his misses coming up short. Let’s just say he is not the first Celtic you want to see walking to the line in a tie game with 27 seconds left, you know?

There’s still room for growth for this Celtics juggernaut as a team, too. It must bug Brown a little bit when Tatum maddeningly defaults into isolation mode at the end of games and quarters. The Celtics superpower — besides their defense, led by the politely ferocious Holiday — is the overall exceptional quality of their starting five. These Celtics will reach their pinnacle when their late-game offense operates with the selflessness and creativity of their usual offense.

It is understood that no question about this team will be answered in full until the confetti falls. But this much is certain right now: Jaylen Brown has been excellent this season, and downright extraordinary lately.

Imagine the possibilities if this is actually who he is for good.