The Boston Celtics turned NBA Finals heartbreak into what so far has been the best offense in league history

This season's version is lapping the field with an offensive rating of 119.9 -- the best offense in NBA history statistically. And as Boston prepares for Saturday's Finals rematch with the Warriors (8:30 p.m. ET, ABC), the Celtics hope their offensive explosion is here to stay.

"It's night and day," Tatum said last month. "The way we are playing at the start of this season compared to the start of last season.

"I just feel like we haven't looked back."

THE CELTICS' TRANSFORMATION failed them during their six-game Finals loss to the Warriors -- Boston's offensive rating fell more than six points compared to the first three rounds of the playoffs -- as Finals MVP Stephen Curry snatched away a chance for the Celtics to raise banner No. 18.

Those struggles ate at Joe Mazzulla all offseason. Revamping the offense was the main focus as he and the rest of the Celtics coaching staff prepared for this season -- even before he was elevated to interim head coach when Ime Udoka was suspended for the season for violating team rules.

"The one thing we looked at was: What were the best clutch offensive teams running?" Mazzulla told ESPN. "We just tried to find the best clutch offenses and what they did and kind of studied that."

And, as Mazzulla spoke to various coaches about different ways Boston could improve its offense, those discussions often revealed similar principles: more spacing, more ball movement and more off-ball screening action.

"We have a really smart team and experienced team and they know we had to reinvent ourselves," Mazzulla said.

"Guys have done a great job buying into that. Now we're just learning about the different ways teams are going to guard us and how we can adjust to that."

The Celtics have eight players averaging at least 3.7 3-point attempts per game and five of them are shooting over 43% from deep. They have dramatically increased their off-ball screening action with an additional seven more per game this season, per Second Spectrum tracking data, and created 1.12 points per chance when doing so -- easily the NBA's best mark.

As a result, the team's offense has produced a dizzying list of accolades:

• The Celtics' 120.8 points per game would be the most any team has averaged over the course of a season since the Denver Nuggets 30 years ago.

• Boston leads the league in 3-point percentage (40.0) and 3-pointers made per game with 16.6, which would be second all time behind the 2020-21 Utah Jazz (16.7).

• The Celtics are on pace to set an NBA record with their true-shooting percentage as a team (which includes 3-pointers made and free throws), sitting at 62.6.

"They share the ball. That's a great starting place," Nuggets coach Michael Malone said after Boston snapped Denver's four-game win streak.

"They make 16 3s a night, and they're getting [those makes] from so many people. [Plus] you have two great one-on-one players in Jayson Tatum and Jaylen Brown, who can get their shot whenever they want."

It wasn't long ago that Boston's star duo was being criticized for lack of ball movement from inside its own locker room, as guard Marcus Smart himself publicly expressed after an ugly collapse against the Chicago Bulls in early November 2021.

"We've had a lot of success early and obviously the beginning of last season was sort of a struggle," Tatum said of his partnership with Brown. "People didn't allow us to have time to kind of work through that. Everybody kind of questioned it, [saying], 'Blow us up, trade one of us.'

"I'm 24 and he just turned 26, and [we are] two of the best two-way players in the league. ... I was never worried, he was never worried, the team was never worried. It was only a matter of time."

After fighting through a shooting slump midway through last season, Tatum has raised his level of play dramatically.

He followed last season's All-NBA first-team honor with a blistering start to 2022-23, averaging 30.5 points per game through Thursday -- he would become the first Celtics player to average 30 for a season if he continues the pace -- while increasing his free throw rate for a fifth consecutive year and firmly ensconcing himself in early MVP conversations.

Brown, meanwhile, is scoring a career-high 26.7 points per game while shooting a career-best 50.7% on volume, making him one of seven players in the NBA this season to average at least 25 points while shooting at least 50% from the field.

"It feels that much better when we've grown from his second year and my first year [2017-18] to now, and how hard we've worked to build the foundation of how we play," Tatum said.

"It's going to pay off one day."

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BEYOND STYLISTIC CHANGES to the team's offense, Boston's failings in the Finals could also be boiled down to something else: a lack of on-ball creators outside of Tatum and Brown.

That left too much of the creation burden on their shoulders and played a role in Boston's demise. It led to the team's signature offseason move: trading for Malcolm Brogdon from the Indiana Pacers. It didn't take long for the deal to pay off.

In the Celtics' season opener against the Philadelphia 76ers, Brogdon flashed skills on back-to-back possessions that the Celtics utterly lacked during last year's playoff run. The former Rookie of the Year is already among the favorites for this season's Sixth Man of the Year award.

On one possession, Brogdon grabbed a rebound, pushed the ball upcourt, attacked the paint and kicked to Williams for a 3-pointer. On the next, he caught a pass on a swing to the corner from Blake Griffin, attacked a James Harden closeout and looped to the rim for a layup.

"Brogdon has obviously helped in bringing a new dimension to what they do," Miami Heat coach Erik Spoelstra said when his team faced Boston for two games last week.

When opposing coaches, scouts and executives are asked about the reasons behind Boston's offensive improvement this season, Brogdon, who is averaging 14.0 points and 3.8 assists per game while leading the NBA in 3-point percentage (49.4), is often the first player mentioned.

"He has been really significant for them," an East scout told ESPN, "because their undoing at times last year was they could get stagnant and predictable."

That certainly isn't the case now because of the weapons Mazzulla has used at his disposal.

Derrick White and Williams are both playing with increased confidence offensively, while Sam Hauser has emerged as one of the league's most lethal 3-point shooters.

"They run some really unique offense," Malone said. "Some small, small pick-and-rolls, a lot of cutting. They do a really good job of off-ball movement, create confusion, and they have a really nice rhythm about them."

Playing without lob threat Robert Williams III, who is still working his way back from September knee surgery but could return by Christmas Day, has forced Mazzulla to lean heavily on smaller lineups. It's given Boston the luxury of hunting for great shots rather than settling for good ones.

"Our spacing," Al Horford said at a Celtics shootaround last week, "is a big reason why we are so successful."

Grant Williams added, "[We are] not stagnating, we are not playing isolation ball. We are trying to get the best shot available no matter who it is."

At some point, the shots will stop falling at quite the same rate -- Brogdon, Williams, Hauser and Horford are each in the league's top 12 in 3-point percentage, and Boston is shooting more than four percentage points better than expected on 3-point shots this season, according to Second Spectrum tracking. But Boston isn't banking on its record-setting offense slowing down any time soon.

"I think we've done a good job of creating a style of play that fits around everybody," Brown said after Boston beat Miami last week. "Being able to score the ball, being able to drive, being able to create those advantages and then shoot.

"We've got to keep playing that style of ball, because it's working."