Jaylen Brown was in the midst of one of the best stretches of his basketball career, and he was feeling it. The Celtics were about to put away the Magic for good, and he sensed it.

Midway through the fourth quarter, Brown delivered a dagger. Jayson Tatum corralled a Magic miss, and gave it to Brown. His hot hands did the rest. He took three dribbles and pulled up from 28 feet. The shot, of course, went in. TD Garden erupted. The Magic called timeout. Brown saluted the crowd.

And on the sideline, his coach showed a rare case of emotion. He pumped his left fist with authority. And he let out a big roar as the Celtics came back to the huddle. Sunday’s victory over the Magic was in no doubt.

“I think the players need to see that sometimes,” Mazzulla said. “I do, like everybody else, care about winning, and I do have fun. And I just thought it was a moment to show, I think we’re starting to play what I would call Celtic basketball.

“From a mentality standpoint, from a toughness standpoint, from a defensive standpoint, and identity, reflecting what it means to play like the Celtics, I think this week we’ve shown that, and I think the crowd has helped that, and I think our players really working to execute and buying in have helped that.”

Mazzulla challenged the Celtics to approach this week like it was the playoffs. With a pair of two-game series against playoff-caliber opponents, he wanted to see how the Celtics would take the challenge of playing with the consistent mindset he has emphasized all season. By sweeping both series, Mazzulla was encouraged. It was a big step toward the type of “Celtics basketball” he wants to see.

“What we’re starting to show, right?” Mazzulla said. “Opponents bring out the best in us, they challenge us, and we don’t back down. We chip away at it, and we respond and we dictate the mindset of the game, the physicality of the game, and we’re just kind of playing with that type of identity. I’ve really seen that, especially over the last four games. We may lose it from time to time, but we have to fight to keep this mindset and identity that we have on both ends of the floor.”

It certainly hasn’t always been perfect. When the Celtics were blown out by the Magic in Orlando last month, it provided them with something of a reality check.

“I think at that point, as we were heading into that Orlando game, we were beating everybody, we were getting wins but we were getting maybe a bit lazy on some small details,” Kristaps Porzingis said. “Offensively, we were kind of a little bit slower and I think from that game, we sat down, we looked at the offense again, cleaned some things up.

“Not that it was like a huge turning point but it was something like, ‘OK, this game we really kind of needed to clean some things up.’”

The Celtics have won eight of their last nine games since, with the lone loss coming to the Pacers in the In-Season Tournament quarterfinals. After Sunday’s win, they were extremely proud of how they finished undefeated this week, given the circumstances. Brown called Friday’s victory the biggest of the season because the Celtics didn’t give in to excuse-making despite being shorthanded and playing on the second night of a back-to-back. Sunday provided a different challenge as they tried to sweep a difficult opponent with an earlier-than-usual 3 p.m. start time, but the Celtics passed that test, too.

“We can’t skip steps,” Brown said. “Certain teams got our number and Orlando’s been one of those teams in the last year and a half. And we wanted to make sure in this stint that we kind of set a tone and got over that hump. And I think we did a good job. I think we could have played better in spots certainly but it was a good test. Back-to-back, coming into an early game, we took the right mentality and we came out on top. And I like that.”

Tatum went as far as to say that last year, he doesn’t think the Celtics would have gone undefeated this week given the circumstances of four games in six nights. It was a way of illustrating how much this group has grown.

“This was a challenging week,” Tatum said. “I know throughout the course of the season, we always talk about we got a long way to go, a lot of things we can work on, which is true. But what we did this week was impressive, I feel like. I’m not certain that last year, we would have won all these games. But playing two really good teams that present different challenges; teams that, especially Orlando, we struggled with in the past. Especially Friday, we had three bigs out and the way that we played in that game, we figured out a way to win. Winning these four games at home, I don’t know what everybody else thought, but it was impressive and I was proud of the way we played. …

“I think we just learn from our mistakes. We’ve learned from things that we didn’t do so well in the past year. We apply them just a little bit better this year from game to game.”

Porzingis still managing injury

Porzingis did not play in Friday’s win because of the left calf strain that he’s still managing. He suffered the injury on Nov. 24 against the Magic and returned after missing four games. He sat out Friday’s second leg of the back-to-back as he and the Celtics tread cautiously.

“To be honest, it was just a cautionary thing,” Porzingis said. “Not playing a back-to-back. But it felt good. Felt good enough that I could have played. It’s just I think the medical staff taking a more cautious approach, especially the first couple weeks coming back from the calf.”

The Celtics have another back-to-back this week when they hit the road to play the Warriors and Kings on Tuesday and Wednesday night. It’s possible Porzingis sits out one of those games.

“That’s something we just started talking about,” Porzingis said. “We don’t have the answer yet. But they know my stance: I want to play in every game they allow me. But of course, they want to be smart with me and my health. Make sure I’m here for the long picture.”