Jayson Tatum, Jaylen Brown combine for 70 points as Celtics outlast 76ers 126-117

New coach, new season, new players in the mix.

Same overpowering and dynamic Celtics.

The Celtics resembled the team they did during their spectacular turnaround last season, earning a 126-117 win over the 76ers at TD Garden on Tuesday. Jayson Tatum and Jaylen Brown poured in 35 points apiece and Malcolm Brogdon chipped in 16 off the bench in his debut.

Boston shot a blistering 56.1 percent from the floor, dominated 24-2 in fast break points and only turned it over 10 times.

“We did a great job maintaining our poise,” said Joe Mazzulla, who earned his first win as a head coach. “We put ourselves in some difficult situations with some of the fouls. Some stuff didn’t go our way, but we didn’t overreact. We maintained our focus and execution.”

The Celtics jumped out to a 9-2 lead early, firing up an already-rowdy crowd even more. Joel Embiid (26 points) bricked a jumper, Tatum buried a 3 and blew a kiss to the fans, and everything was going Boston’s way in the opening minutes.

The 76ers responded with a 12-2 run of their own, however, and eventually built a 29-24 edge through 1. James Harden (35 points) poured in 16 points, hitting all eight of his free throws after the Celtics fouled him on three separate 3-point attempts. The Celtics effectively doubled Embiid and held him to just one point in the quarter.

Grant Williams was sharp for the Celtics, playing steady defense and drilling a corner 3 that caused De’Anthony Melton to crumble to the ground.

Boston used a strong second quarter to tie the score at 63 heading to halftime. Brown was automatic in the mid-range, Tatum continued to show an improved ability to finish in traffic, and Brogdon slithered into the paint for a steady stream of buckets.

Al Horford, Noah Vonleh, Williams, Blake Griffin and, yes, big man Marcus Smart made life difficult for Embiid. The Celtics caused turnovers and stymied the 76ers’ playmakers.

“Just being able to have the freedom to make plays,” Brown said. “Our system is catered to what we do best.”

The Celtics turned it over just four times in the half, outrebounded a bigger Philadelphia team, 17-15, and shot 54.5 percent from the floor.

The third quarter was chippy to start, as Smart and Embiid got tangled up near the basket in the opening minute. Smart, who fell to the floor, was hit with both a personal and technical foul. Embiid escaped unscathed following the mini kerfuffle.

Smart was confused by the verdict and pleased with himself for not overreacting.

“I could have cracked his head open, but I didn’t,” Smart said.

The Celtics used an 8-0 flurry, behind Tatum’s continued brilliance, to extend their lead to 90-78. They held a 98-88 edge through three following a dynamite 35-point third quarter in which they kept pushing the pace.

Boston regressed to the mean offensively in the fourth quarter, but Philadelphia couldn’t orchestrate a comeback. Horford delivered a dagger from the corner in the final minutes, and the 76ers ran out of time.

It was a successful debut for Mazzulla, who appreciated the love he got all night.

“I’m grateful to the players for the relationship that we have, and I’m really grateful that they trust me and trust each other, and that they were able to show that type of buy-in,” Mazzulla said.