‘Yo, Joe, we did it!’ From morning coffee to late-night champagne, inside the wild day the Celtics became NBA champions. - The Boston Globe (2024)

“I told him, ‘Don’t you push my buttons this morning,’ ” Camai said, smiling.

Next, Mazzulla took Nike, their rottweiler, for a walk before leaving for work. Sometime around then, Celtics superstar Jayson Tatum and his trainer, Nick Sang, were arriving at the Auerbach Center, following a similar theme.

Yes, the Celtics had missed their chance to sweep the Mavericks in Game 4 three days earlier, but there was no need to change anything. Tatum received his usual pregame treatment and completed a weightlifting session, eager for the opportunity the night would bring, but hardly overwhelmed by it.

Hours later, at 12:38 Tuesday morning, Tatum glided across the green and white confetti that coated TD Garden’s parquet floor. He was wearing an NBA champions T-shirt and hat that had been drenched in beer and champagne during the first of several locker-room celebrations. He yelled out that he really wanted a peanut butter and jelly sandwich, and then he saw Mazzulla doing a television interview.

“Joe!” Tatum boomed. “Yo, Joe! We did it!”

Mazzulla looked above the lights and cameras toward Tatum. They were both smiling.

“I told you!” Mazzulla yelled.

“We did it!” Tatum said once more.

At last, it was time to exhale. The Celtics’ 106-88 win over the Mavericks that clinched the series, 4-1, and solidified the franchise’s NBA-record 18th championship was the final, indelible chapter of this remarkable year.

The Celtics won 64 regular-season games and marched through the playoffs with a 16-3 mark, rinsing away nearly a decade of shattered hopes as they went.

“All of the moments where we came up short, felt like we let the city down, let ourselves down, all of that compiled is how we get to this moment,” said forward Jaylen Brown, who was named Finals MVP. “And it makes it feel even that much better that we had to go through the journey, the heartbreak, the embarrassment, the loss, to get to the mountaintop.”

Tatum recalled two years ago, when the Celtics took a 2-1 Finals lead over the dynastic Warriors before losing three games in a row and hearing them celebrate in the bowels of TD Garden. He said it was devastating.

He knows that to be truly considered an all-time great, particularly for this storied franchise, all measurements begin with banners.

“So now I can, like, walk in those rooms and be a part of that,” Tatum said. “It’s a hell of a feeling. I dreamed about what it would be like, but this is 10 times better.”

Camai Mazzulla asks her husband to give her some signal when he walks onto the court to indicate everything is going to be fine, that he has things under control. She knows that everything will be fine, but it makes her feel better anyway.

When Mazzulla walked onto the court Monday night to coach the biggest game of his life, he gave his wife a subtle nod.

“He’s very confident,” she said. “He said all season, ‘I know we’re going to win and I know we’re going to win at home.’ He just said, ‘I hope it’s not in a Game 7.’ ”

But there would be no need for Game 7, not with this team. The Celtics removed most of the suspense from Game 5 rather quickly, subduing Mavericks stars Luka Doncic and Kyrie Irving and racing to this wire-to-wire win in which they led by double digits for the final 27 minutes.

Just like that, new chapters were added to so many of their stories.

Al Horford thought back to his free agent meeting with co-owner Wyc Grousbeck in 2016 that led to his first stint in Boston. He remembered being enchanted by Grousbeck’s large, shiny 2008 title ring, and he remembered the words of former president of basketball operations Danny Ainge.

“[Ainge said] you can win championships in many places, but there’s nothing like winning in Boston and nothing like winning as a Celtic,” Horford said.

Jrue Holiday, who was traded to the Trail Blazers last fall in the seismic deal that sent Damian Lillard to the Bucks and seemingly tipped the scales in the Eastern Conference, thought back to when he received a text message from Tatum telling him the Celtics were interested in bringing him to Boston. President of basketball operations Brad Stevens then made it clear with a phone call.

“It’s been a hell of a journey,” Holiday said.

Kristaps Porzingis had never won a playoff series before being traded to the Celtics and he embraced every part of this team and city. Then his postseason was derailed by calf and ankle injuries, and he could hardly believe it.

He was cleared to return in Game 5 and received a massive ovation when he came onto the court for warm-ups before toasting the crowd with his cup of water.

“Tonight was the night,” Porzingis said. “I was like, ‘Listen, I’m going to give it everything I have.’ ”

One of Derrick White’s front teeth was severely chipped during a second-half collision; he said two others were dislodged. But when he sheepishly smiled during the postgame celebration, he said he would have willingly given up all of his teeth for a title. That would not be necessary.

At the final buzzer, confetti sprayed as the crowd inside erupted and the crowd outside swarmed Causeway Street to continue the party.

Assistant general manager Mike Zarren, who was a Celtics fan long before taking this job, watched the first half with his father, Harvey, in the upper-deck seats they have owned since TD Garden opened nearly 30 years ago, and the two made it down toward the court for the rest. He started crying as the final seconds ticked away.

Mazzulla, who arrived here as a relatively unknown assistant five years ago and has now completed one of the swiftest ascensions imaginable, thought back to all of the players and coaches who helped construct this franchise, who helped make this all possible.

Stevens, who prefers to operate outside of the spotlight, shuffled off the stage after the trophy presentation and waited in the tunnel to congratulate one person after another as they passed him.

Tatum found his 6-year-old son, Deuce, amid the din, and practically lifted him to the rafters.

“He told me that I was the best in the world,” Tatum said later. “I said, “You’re damn right I am.’ ”

Inside the Celtics’ locker room, the party continued. Music blared as players puffed on cigars and wore ski goggles as beer and champagne sprayed into the air, onto heads, and into mouths.

But already there were thoughts about what comes next. Brown said those who doubted the Celtics this season were certain to return, and he vowed to silence them once more. Co-owner Steve Pagliuca said this mind-set was not surprising.

“I’m sure they’ll take a day off and then start figuring out how we can do it all again next year,” he said. “Once you reach the mountaintop, you want to get there again. It’d be really special if we can do that.”

As the clock ticked past 1:30 a.m., though, Tatum was focused on a more imminent hunger. Mostly, he was still looking for that elusive peanut butter and jelly sandwich.

“Yo,” he said, “is there any food around here?”

Read more about the Celtics’ NBA championship

• Dan Shaughnessy: A torch has been passed: Jaylen Brown, Jayson Tatum join the champions club and help Celtics raise Banner 18
• Al Horford is an NBA champion. Finally. | Chad Finn
• When will the Celtics hold their championship parade? Here’s what we know so far.
• ‘An unbelievable feeling:’ Celtics celebrate first NBA title since 2008; fans take to the streets outside TD Garden
• ‘I’d lose all my teeth for a championship:’ Derrick White smiles through the pain after chipped tooth in Game 5
• Jaylen Brown named NBA Finals MVP after 21-point performance in Game 5
• Payton Pritchard beats the buzzer again, making longest shot in the NBA Finals in more than 25 years
• With one more rough shooting night, Kyrie Irving’s fruitless Finals return to Boston draws to a close

Adam Himmelsbach can be reached at adam.himmelsbach@globe.com. Follow him @adamhimmelsbach.