Philadelphia center Joel Embiid, right, is separated from Boston guard Jaylen Brown, left, are separated after an altercation with Marcus Smart, not pictured, during Tuesday’s game in Boston. Charles Krupa/Associated Press

Marcus Smart and Joel Embiid have a history of confrontation, and the two got reacquainted with another dust-up during Boston’s season-opening win over the 76ers on Tuesday night.

But when the dust settled, it was Smart who took exception to their latest episode.

On the first play of the third quarter, after Jayson Tatum missed a shot, Embiid pulled down the rebound over Smart, whose left arm got caught in Embiid’s grasp. He went down after Embiid pulled his arm and then hit him with an elbow to his back. Smart, clearly angry about what happened, then grabbed at Embiid’s leg, and the center fell to the floor before the teams had to be separated as tempers flared in an emotional exchange.

After the game, Smart – who was the only one who was issued a technical foul after a video review – ripped Embiid for what he believed was a dirty play.

“Went for a rebound. Basketball play. Went for the steal. Basketball play,” Smart said. “Referee blows his whistle, calls a foul. I stop play, my arm’s still stuck in there and he tried to break it. And then I’m the only one who gets a tech. Everybody saw it. I don’t have to keep talking about it. If I did that, I’m probably ejected, suspended three games, four games, fined. But the fact that I was the only one that got I guess something out of that is kind of beyond me. Especially (being) defending DPOY (Defensive Player of the Year) and that’s how he gets treated.

“It’s tough. But, like I said, it’s maturity. I could have cracked his head open but I didn’t. And that’s the maturity we have. So we move on from it. It is what it is. And we control what we can control.”

Embiid said he wasn’t sure what happened and chalked up the emotional sequence to an intense rivalry.

“They had called a foul and then I walked away and next thing I know my foot is getting caught up and I slipped and next thing Jaylen (Brown) was on top of me and I don’t know,” Embiid said. “It’s basketball. Emotions, first game of the season, rivalry, Boston-Philly, a lot of intensity … so, it’s all good.”

Brown quickly ran to Smart’s defense at the beginning of the dust-up and put his hands on Embiid before wagging his finger at the Sixers center. He was trying to send a message.

“I thought the duration of the game, Embiid was getting away with a lot of unnecessary pushing and shoving,” Brown said. “Just being a big guy, that’s what he does. But he was throwing his weight around a little bit. I had said something before that moment, but they kind of let it go, brushed it off. So in that play … it seemed like he was trying to hurt Smart in a sense.

“Instincts just came right over. Ended up being nothing, ended up being a play-on, nobody got hurt. We just ended up finishing the game, played some good basketball. But we got each other’s backs out there and we’re not taking no mess this year.”

Embiid was eager to put the game behind him and focus on Thursday.

“I’m not worried about Boston,” he said. “We have 81 more games. We’ve got Milwaukee coming up.”

ONE OF THE BIGGEST cheers during Tuesday’s game at the Garden came late in the first quarter when Blake Griffin made his debut as a member of the Celtics on the parquet, who was taken aback by the massive ovation.

“I definitely appreciated that,” Griffin said. “One thing about this crowd, you got keep their respect by playing hard. If you do that and do the little things, they will appreciate you here. You don’t have to score 50 or be JT or JB. If you contribute to this team in a winning way, they appreciate you and that’s what I appreciate about them.”

Griffin scored just one point in eight minutes but grabbed five boards, tying him for the second most on the team. Griffin acknowledged he was still working his way back into top form after signing with Boston a week into training camp. He suited up for two preseason games.

“Conditioning-wise, just trying to figure out a new team and all that,” Griffin said of his outing. “I feel great. (The training staff) have done a great job. It’s just about time. I felt good out there but I can go to another level for sure.”

In the meantime, Griffin is just enjoying watching his young All-Star teammates look like they are in midseason form against a potential contender in Philadelphia.

“You can see it everyday in practice. They are ready to go,” Griffin explained. “They take this crap very seriously. They are on a mission.”

BEFORE JOE MAZZULLA picked up his first-ever win leading the Celtics as interim coach, he almost didn’t get that opportunity. When the Jazz and Danny Ainge were looking for a new head coach this past offseason, they landed on Celtics assistant Will Hardy to lead a rebuild in Utah. Mazzulla was part of the interview process as one of the up-and-coming young coaches in the league, which is why Ainge wanted to poach him to the Jazz.

But Celtics co-owner Wyc Grousbeck said he blocked any move to also grab Mazzulla, who was still an assistant coach on Ime Udoka’s staff at the time. And it was a good move in hindsight as Mazzulla was promoted to interim head coach after Udoka’s yearlong suspension for violating team policies.

“I prevented Danny from stealing him this summer because I told Danny I’d fly to Utah and personally strangle him if he did. You can quote that,” Grousbeck said in a radio interview. “You can take one person, an assistant, and make them a head coach, which they did with Will Hardy.

“Then they also wanted Mazzulla, and I was like, ‘That’s it, you’re crossing the line and we’re not having it.’ That was just when Joe was senior assistant with us and now, all of a sudden, he’s interim head coach. We believe in him and I think the players believe in him for sure.”

Mazzulla, 34, doesn’t have any head-coaching experience aside from two seasons at the Division II level a few years ago. But the Celtics handed Mazzulla the keys to a title contender.

“He’s got intensity for being a small-sized guy, point guard,” Grousbeck said. “Sort of been an assistant, never been a head coach in the NBA. Now he’s the interim coach for the Celtics. It’s a big ask for a 34-year-old. Then you meet Mazzulla and you’re like, ‘Alright, this could really work.’ I’ve heard nothing but raves about him over the last few years from Danny, while he was here, and Brad (Stevens) and Ime.”

The players have responded well to Mazzulla’s leadership and guidance so far. It helps that he’s been on the Celtics coaching staff since 2019 when then-coach Brad Stevens brought him in, so there was already a natural connection. Mazzulla hasn’t made the transition about himself much, but did get some perspective after Tuesday’s win about what a cool opportunity he currently has with the Celtics.

“At the end of the game, the ‘Let’s go, Celtics’ chant, we picked up right where we left off,” Mazzulla said. “I pride myself in the Boston fans and the city of Boston and when they’re cheering for you it means you’re doing something right.”