Pritchard had made little impact in the series, save for a similar heave in Game 2. When he stepped into his latest prayer, the TD Garden crowd rose in anticipation and then roared its approval. The Celtics, certain now that the night and season belonged to them, ran away from the Mavericks with a 106-88 victory to secure their record-setting 18th championship, breaking a tie with the Lakers, their chief rival. The title is Boston’s first since 2008 following Finals losses in 2010 and 2022. Jaylen Brown was named Finals MVP, receiving seven of the 11 media votes to beat out Jayson Tatum.

“I can’t even put into words the emotions,” Brown said. “I’m blessed and I’m grateful. My teammates were great. They allowed me to lead us on both ends of ball, and we just came out and performed on our home floor. [Finals MVP] could have gone to anybody. It could have gone to Jayson. I can’t talk enough about his selflessness and attitude. We did it together as a team, and that was the most important thing.”

Boston’s clinching victory capped one of the most dominant seasons in recent years. The Celtics went 80-21 overall — 64-18 in the regular season and 16-3 in the playoffs — and won the Eastern Conference by 14 games over the No. 2 seed New York Knicks. The Celtics’ breezy postseason run, which included an Eastern Conference finals sweep of the Indiana Pacers, was the fastest title chase since the Golden State Warriors went 16-1 in 2016-17. Their Game 4 blowout loss to the Mavericks on Friday was the Celtics’ only defeat in their final 12 games.

To put away Luka Doncic and the Mavericks for good, the Celtics turned to their textbook winning formula of balanced scoring and high-volume outside shooting and energetic defense. Tatum shook off a slow start to take over in the fourth quarter, finishing with a game-high 31 points to go with 11 assists and eight rebounds. Brown added 21 points, and Jrue Holiday chipped in 15.

“These last seven years have been a roller coaster, up and down,” Tatum said. “I had to listen to all the s— that people said about me. Tonight, it was worth it. Oh, my God. We came together and we won a championship. Banner No. 18 has been hanging over our head for so many years. To know that we’re going to be engraved in history, it still hasn’t registered. I’m just still trying to process it all. But we did it.”

Doncic finished with a team-high 28 points — many of them coming after the Celtics were already up big — and Mavericks guard Kyrie Irving was held in check again, finishing with 15 points on 5-for-16 shooting. Dallas had no reliable backup plan with its star guards struggling early, shooting just 11 for 37 (29.7 percent) from deep.

“I’m sad we lost,” Doncic said. “I’m proud of every guy that stepped on the floor, all the coaches, all the people behind [the scenes]. Obviously, we didn’t win the Finals, but we did have a hell of a season.”

Pritchard’s backbreaking shot was his only basket of the night, but it gave Boston a 67-46 halftime lead, prompted Brown to call his teammate a “f—ing legend” and led Celtics Coach Joe Mazzulla to call him “one of the best competitors and one of my favorite people in the world.”

The Celtics, who never trailed, pushed their lead to 26 points in the third quarter before cruising to a victory against a Mavericks squad that simply couldn’t match their energy. Even so, the TD Garden crowd spent much of the first half managing its collective anxiety: Tatum, who missed his first four shots, drew loud, relieved cheers when he finished a drive through contact and pounded his chest with both hands midway through the second quarter. After a dry spell to open the fourth quarter, Brown found a cutting Kristaps Porzingis, who returned after missing two games with an ankle injury, for a thunderous dunk that brought the building to its feet.

Tatum and Brown each heard “M-V-P” chants as Boston put the finishing touches on its victory. When Mavericks Coach Jason Kidd pulled his starters in the closing minutes, Irving offered congratulatory hugs to Tatum and Brown, his former teammates on the Celtics, and Boston’s coaching staff. Once Mazzulla emptied his bench with less than two minutes to play, Tatum held his head in disbelief before embracing Brown. Buckets of green confetti poured from the rafters after the final buzzer, and Tatum lifted his young son, Deuce, into the air to celebrate.

In a raucous postgame locker room, Celtics owner Wyc Grousbeck smoked a cigar, members of the coaching staff sprayed champagne and the players took turns posing with the Larry O’Brien Trophy and a green championship belt. Written on the white board, underneath a sign that read “Every possession matters,” were four words: “Noon flight to Miami.” The celebrations will continue in South Beach.

Despite their gaudy record and strong finish, the Celtics were never fawned over quite like super teams of the past. There were some obvious explanations: They lacked an all-time icon such as Michael Jordan, Shaquille O’Neal or Stephen Curry; they benefited from the postseason injury absences of Miami’s Jimmy Butler, Cleveland’s Donovan Mitchell and Indiana’s Tyrese Haliburton; and they spent much of this season trying to escape the shadow cast by their previous playoff disappointments.

Regardless of the competition, Boston returned as a better, deeper, more focused and more disciplined team than the group that blew a 2-1 lead in the 2022 Finals to the Warriors and fell into a 3-0 hole in the 2023 Eastern Conference finals against the Miami Heat.

Thanks to the offseason additions of Porzingis and Holiday, Celtics President Brad Stevens assembled the NBA’s best collection of talent and Mazzulla oversaw a complete team, filled with complete players, that started 11-2 and never looked back. Boston ranked first on offense and second on defense in the regular season, then ranked fourth on offense and third on defense in the playoffs. Defying their lasting reputation for blown leads and late-game misadventures, the Celtics went 21-12 in regular season games that were within five points in the final five minutes and 6-0 in such games during the playoffs.

“Over the last couple years, we had some tough losses at home in the playoffs,” Tatum said. “We’ve lost the NBA championship at home in front of our fans. We had a chance to beat Miami a few years ago and lost that one. To have the biggest win that you could have in front of your home crowd — I felt like that was really important to go out there and do everything in my power to make sure we won this game.”

The tightly wound Mazzulla successfully pushed Tatum and Brown to take better care of the ball and to trust his offensive philosophy, which relied heavily on catch-and-shoot three-pointers. Remarkably, eight different Celtics players made at least 100 three-pointers this season.

On defense, the Celtics’ versatility was their calling card; they used an aggressive, switching scheme to make life difficult for opposing perimeter stars such as Doncic and Irving. Porzingis’s arrival helped shore up their interior defense and rim protection while keeping the miles off 38-year-old center Al Horford, who won his first championship in his 17th season.

“You can’t have a philosophy or a way of playing if you don’t have a group of guys that are willing to buy into it and be disciplined,” Mazzulla said. “This group of guys has been through so much in the league. They know what it takes. It was a joy watching the guys just grow as a team throughout the year but also really work at it. There’s a group of guys in the locker room that decided they wanted to win on day one, and credit to them.”

Boston’s long-awaited championship finally completed a narrative arc that began with then-Celtics president Danny Ainge’s 2013 blockbuster trade of Kevin Garnett and Paul Pierce to the Brooklyn Nets for a package of role players, future first-round picks and pick swaps. By parting with two of the faces of their 2008 title team, Boston was able to secure draft picks it used to acquire the two faces of this year’s title team: Brown in 2016 and Tatum in 2017.

The full-circle moment was only possible after some painful moments and countless reinventions. Boston hired Stevens from Butler University to guide the rebuilding effort, and he won only 25 games in his first season. The Celtics gradually climbed up the standings, but they cycled through countless stars — Isaiah Thomas, Irving, Kemba Walker and Gordon Hayward, among them — as Tatum and Brown matured.

Brown recalled a 2017 vacation in Spain when he received a 4 a.m. phone call from Ainge.

“Don’t ask me why I was up,” he said. “Danny asked me, ‘How do you feel about Jayson Tatum?’ I remember I played with him at the Top 100 camp. He was my roommate at [Kevin Durant’s] elite camp. We played on the same team in so many different [high school games]. At the Under Armour all-American game, we were roommates again. I had a lot of experiences with him. There was a lot of respect. I said, ‘I think it’s a great choice.’ Fast forward from there, we’ve been winning ever since.”

As the prominent faces around them came and went, a through line emerged for Tatum and Brown: Boston was good enough to make deep playoff runs but not great enough to win it all. The Celtics reached the East finals in six of the past eight seasons, but they advanced to the Finals just once before this year and crumpled on the championship stage against Curry, Draymond Green and Klay Thompson.

Hitting the wall repeatedly led to Ainge’s exit and Stevens’s promotion from coach to president in 2021. When Stevens’s coaching successor, Ime Udoka, was fired in 2023 following an improper relationship with a female co-worker, Boston turned to the 35-year-old Mazzulla, who was only a few years removed from coaching in the G League.

As the personnel changes and off-court drama unfolded around them, Tatum and Brown blossomed into all-NBA players and the Celtics resisted calls to break up their star wing duo. In a series of brilliant trades, Stevens acquired Horford, Derrick White, Porzingis and Holiday to build an experienced two-way team around his two-way star forwards and load up for revenge after a humiliating season-ending loss to the Heat last year in Game 7 of the East finals.

“We learned from all of our mistakes,” Brown said. “All of our adversity has made us stronger and tougher. All season you could see it. We made all the sacrifices. We played both ends of the ball at a high level. We didn’t skip any steps. All of the moments where we came up short, where we felt like we let the city down, let ourselves down, all of that compiled is how we get to this moment. The doubters may be quiet now, but they will be back next year with something to say.”

Sure enough, the Celtics channeled those painful memories into eight months of beatdowns, erasing any doubts that they were the league’s best team this season.

“With the Celtics, everybody knows we only hang up championship banners [in the TD Garden rafters],” Tatum said. “It’s been a while since we’ve won one. … You [media] guys will probably say we didn’t play anybody to get here. So we’ll just have to do it again next year.”