Derrick White was the Celtics’ offensive catalyst throughout Friday’s game against the Heat, so with Boston rolling early in the fourth quarter and White still scorching, he earned the chance to fire up one ambitious attempt.

This step-back, fadeaway try from the top of the key was careening long, but it thudded off the backboard and slid through the net anyway. White turned to Boston’s bench and sort of shrugged after the dose of good fortune, but the Celtics were happy to take the points and push to a comfortable 129-116 win that snapped their two-game losing streak.

“Yeah. I don’t know,” White said later. “I think I made a few in a row, and everybody was like, ‘There was no chance you were driving on that one.’ So I just tried to get some space, and the bank was open.”

That fortunate bounce was part of a fourth-quarter eruption for the Celtics, who drained six 3-pointers over the first three minutes to finally create separation in this tense game against an undermanned but feisty Heat team. The Celtics made 10 of 15 3-pointers in the final quarter and 21 of 43 overall (48.8 percent).

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“I feel like sometimes shot-making is contagious,” said forward Sam Hauser, who hit 4 of 5 3-pointers in the fourth. “And once you see a couple guys make a couple, then you make a couple, then it’s like you just feed off each other’s energy. And sometimes you have quarters like that where it’s just an explosion.”

White finished with 33 points, 6 assists, and 4 blocks, and Jaylen Brown added 30 points, 9 rebounds, and 7 assists for the Celtics, who shot 53.7 percent from the field.

When that late surge arrived, it became clear that coach Joe Mazzulla did not want to disturb it. He left backups Hauser, Hugo González and Anfernee Simons in for the entire period.

González hit one 3-pointer to contribute to the onslaught but was more impactful at the other end, where the rookie wing turned into the defensive backbone of Boston’s smaller lineups. He flew around the court and found himself matched up against Heat big men Bam Adebayo and Kel’el Ware.

“I think that’s who he has to be for us,” Mazzulla said. “He didn’t play perfectly but played with a level of energy. [He showed] a level of awareness and execution on the offensive end, playing [center] for us at times and creating advantages for us.”

Hugo González (right) reacts after Sam Hauser made one of his four 3-pointers in the fourth quarter as the Celtics pulled away from the Heat.Matthew J. Lee/Globe Staff

Ware had 24 points and 14 rebounds to lead the Heat, who were playing their second game in as many nights, and were missing five of their top 10 rotation players, including Tyler Herro and Andrew Wiggins. So rookies Kasparas Jakucionis and Myron Gardner, who had played a combined 18 minutes all season, were thrust into prominent roles.

Nevertheless, Miami created issues for the Celtics and lingered through three quarters by owning the backboards. The Heat grabbed 17 offensive rebounds, tallied 24 second-chance points and attempted 20 more shots than the Celtics.

Mazzulla often harps on the importance of winning these margins, and this destruction could have been costly. But the Celtics’ small lineups negated this vulnerability by capitalizing at the other, where they used their speed to confuse the Heat and generate open 3-pointers. Of course, it helped that they made so many.

“It’s a tradeoff, and at the end of the day, each game is going to tell a different story,” Mazzulla said. “It’s easy to say it looked like it didn’t go well, but what went well was our offense, and they weren’t able to switch [on screens against] us, they weren’t able to steer us, they weren’t able to keep us out of the paint, and we were able to create a ton of two-on-ones with our speed. So, I thought that was the tale in the second half.”

The Heat stretched their lead to 80-73 on a Jakucionis 3-pointer with 5:51 left in the third quarter. But the Celtics responded with a gradual 8-0 run. Then a free-throw contest broke out. The teams combined to take 25 foul shots in the third quarter, and Boston took a 92-89 lead to the fourth. Then the 3-point barrage arrived.

Hauser hit one, and González came up with a steal that led to another Hauser dart that stretched the lead to 98-91. With Boston leading by 4, White drained a spinning step-back, and Simons added one from the right corner to make it 104-94, the first double-digit advantage for either team.

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