At this point last season, the Celtics boasted an offensive rating of 120.6. By season’s end, they were at 119.5, second-best in the NBA behind the eventual champion Oklahoma City Thunder.

Boston’s offensive rating through 23 games this season is — somehow, shockingly — even better: 121.9. Only the Denver Nuggets and Knicks rank higher.

Think about that: Jayson Tatum has yet to suit up, the Celtics lost a 17-point-per-game player in Kristaps Porzingis this offseason, and their offense, rather than cratering, has actually improved, at least in the modest sample size we’ve seen thus far.

How? Jaylen Brown’s performance as Boston’s new leading man has certainly helped. He’s scoring 29.0 points per game — including 12 games with 30-plus points and three with 40-plus — while also averaging 4.9 assists, which would both be career highs for the 10th-year pro.

Around him, the Celtics’ top shooters have settled in after shaky starts. With Derrick White, Payton Pritchard and Sam Hauser all upping their efficiency, Boston ranks third in the NBA in both field-goal percentage and 3-point percentage over its current stretch of nine wins in 11 games.

“I think we’re definitely going through a stretch of shooting luck, that’s for sure, that we weren’t going through at the beginning of the season,” head coach Joe Mazzulla said after Friday’s 126-105 win over the Los Angeles Lakers. “We’re definitely shooting the ball better than we were. So that does make everything seem better. But I think you come into the season with an identity and a level of execution that you want to have, and then you learn more about your team. And so, obviously, as we continue to evolve offensively and have guys in different spots, playing different lineups, working the reads, (we’ll learn) what the matchups are, what the coverage is, what the spacing should be.”

The impact of Boston’s role players can’t be ignored, either.

Energy and defense are the top priorities for young wings Jordan Walsh, Josh Minott, Hugo Gonzalez and Baylor Scheierman, but all four are also shooting better than 43% from 3-point range. Anfernee Simons is close behind at 41% on 6.0 attempts per game, even as his night-to-night consistency has wavered in his new role as the Celtics’ sixth man.

Walsh, in particular, has upped his offensive production lately, scoring at least 14 points in three of Boston’s last four games (after doing so zero times in his first 78 career appearances).

Neemias Queta is putting together a career year as a first-time starting center (10.1 points, 8.0 rebounds) and spearheading one of the NBA’s top offensive rebounding outfits. The Celtics rank seventh in offensive rebounding percentage, sixth in offensive rebounds per game and fifth in second-chance points per game.

“I feel like you’re never perfect as a team, and you’re always learning and growing together,” Hauser said. “And we’ve only played 23 games with this group together, so you get 82 of them to figure out what works and what doesn’t and set yourself up for success in the playoffs. But yeah, I mean, we’re doing well right now. We’re throwing the fastballs when the fastball is there, and trying to work on our changeup and slider, I guess you could say.”

Pritchard believes the Celtics “still … have another step that (they) can even go” offensively, and not just because Tatum could return from Achilles surgery at some point this season.

“Everybody overanalyzes the beginning of the year so much,” he said. “It’s just like, we’re trying to figure out roles. Everybody’s in a different role. Different offense from the couple years we played, and different shots. But we’re slowly starting to figure out when’s the time to be more aggressive in certain moments for guys like me — obviously, like, JB, D-White, they’re going to be aggressive all game. But once everybody figures that out, that’s what makes the offense great.”