Celtics score a franchise-record 53 points in first quarter in rout against Heat – The Boston Globe

“We didn’t do that,” Mazzulla said. “We kept fighting for good looks, the next best look, and I thought that kept the momentum going.”

When the dust settled after this historic opening quarter, the Celtics had scored a franchise-record 53 points and raced to a 20-point lead behind a startling display of shot making. Their defense afterward was imperfect, but it did not matter in this 147-129 win in front of an audience that included Tom Brady.

“That first quarter,” Hauser said, “was unbelievable.”

The Celtics’ first-quarter point total and their 11-of-15 3-point shooting were franchise records. Jaylen Brown (20) and Hauser (17) became the first Celtics teammates in the play-by-play era (since the 1996-97 season) to score at least 17 points apiece in the same quarter.

Boston actually trailed Miami by 1 point with just over four minutes left in the first before closing the period with a loud and masterful 24-3 run.

Brown put another notch in his MVP-caliber season by pouring in 43 points on 17-of-29 shooting. He was disheartened by a rare off night in Monday’s loss to the Hawks, but confident it would not be repeated.

“I didn’t like how that game went,” Brown said, “so I wanted to come out with an aggressive mind-set tonight and make up for that last game.”

Jayson Tatum registered his first triple-double of the season, with 25 points, 18 rebounds, and 11 assists. Despite the impressive stat line in yet another Celtics win, Tatum stressed that he is still working to regain his All-Star form after missing the first 62 games because of last May’s Achilles injury.

When asked after Wednesday’s win how close he is to truly being back, he said he could not attach a figure to his recovery. But he said he feels the progress that has also been quite visible.

“It sounds cliché, but I feel a little bit better every game,” he said. “I don’t know how long it’ll take to get back to what I was, or hopefully better, but the goal is to continue to stack days.”

The Celtics shot 58.3 percent from the field and made 21 of 44 3-pointers. Miami actually outshot Boston from beyond the arc by making 24 of 47 (51.1 percent). The Heat hit 11 in the third quarter, matching the Celtics’ franchise-record total from the first. But it was not enough.

Still, Miami’s response allowed the Celtics to extract some teaching moments from an otherwise feel-good night.

“The sign of a great team is even after a great quarter you come back and do it again,” Brown said. “I thought in the second quarter we allowed some slippage and they took advantage. So, still some stuff to clean up.”

Brown scored the Celtics’ first 11 points, and they opened the game by making 10 of 12 shots and 5 of 6 3-pointers. Despite this initial surge, though, they trailed, 30-29 with 4:15 left.

Then Boston uncorked one of the most dominant stretches of this season. Hauser, who was 5 for 5 from the arc in the quarter, drilled four over the final 4:14.

Baylor Scheierman came up with a steal and flipped the ball over his shoulder to Brown for a reverse dunk. The dam was opened.

Hauser’s fifth 3-pointer, with 32 seconds left, set up a two-for-one chance. Tatum air-balled a 3-pointer on the final play, but Payton Pritchard slid in for the putback to make it 53-33.

“Just high-level shot-making on both ends,” Tatum said.

The second quarter was more, well, normal, with Tatum leading the way after having his first quarter disrupted by foul trouble. The forward had 10 points and eight rebounds and Boston outscored Miami, 27-24.

At the end of the second, Derrick White lofted an alley-oop to Brown, who converted the layup with 1.5 seconds left. White then noticed Heat guard Pelle Larsson roaming free at the other end, so he broke into a full sprint and got there in time to disrupt his last-second attempt. The Celtics went to the break with an 80-57 lead.

Boston led, 104-80, with four minutes left in the third, but Miami punched back with three 3-pointers over the final 65 seconds, with a buzzer-beater by Davion Mitchell pulling the host within 112-102 after its 45-point period. The Heat sliced the deficit to 9 early in the fourth, but a pair of mid-range jumpers by Hauser and a Tatum 3-pointer ensured there would be no collapse.

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