After Oshae Brissett didn’t play in the Celtics’ season opener, Joe Mazzulla was planning on putting in his new forward to start the second quarter of Friday’s home opener.

But those plans changed.

The Celtics found themselves down 13 to the Heat with five minutes left in the first quarter. They looked flat and slow. Mazzulla assigned Brissett to change that, and he accepted. Two minutes later, his impact was felt. As the C’s were storming back, Jaylen Brown missed the free throw on a three-point play, but Brissett got the offensive board. Moments later, on the same possession, Al Horford missed a 3-pointer, but Brissett flew in again for an offensive rebound, and the ball ultimately found Sam Hauser for a 3-pointer.

Just like that, the Celtics had finished a five-point trip to cut their deficit to only three. Brissett’s effort was a game-changer.

“He was the sole reason that we got back into the game, and I told him that,” Jayson Tatum said. “He came right in, and we were kind of flat, his energy, his offensive rebounding, giving us second and third chance opportunities was big. And that’s his job. For him to come do that, to not play last game and come in today and give us the spark to turn the game around was huge. And that’s what I love about our team.”

It was a strong first impression from Brissett, who endeared himself to his new home crowd with his hustle. His box score doesn’t stand out – two points, five rebounds (three offensive) in 14 minutes – but his stint mattered.

“That’s me. That’s who I am as a player,” Brissett said. “Every night I’m going to try to do that no matter who we’re playing, no matter what night it is. But we’ve got real stars on this team. So me coming in, just being myself, not trying to do too much, not trying to prove that I can do anything else even though they all know I can. But it’s OK. So I should just be myself, go out there and just try to do all the little things to win us games.”

Brissett’s spark seemed to be contagious. Mazzulla has been preaching a need this season for the Celtics to crash the offensive glass and create extra possessions. They only got seven in the first game. But on Friday, they brought the energy consistently. With Brissett setting the tone early, the C’s finished with 16 offensive rebounds that led to 23 second-chance points, the latter a number they topped just twice last season.

“I still think that’s the area we can get better,” Mazzulla said. “We still gave up some timely ones, right? But, we got timely ones. and so we’re never gonna play perfect, but I thought Oshae’s timely offensive rebounds in the first half were tremendous. I thought, Jaylen, Jrue (Holiday) came back and got one. Jayson got one, like we got some timely physical rebounds. So it’s important that we fight to do that, as many possessions as we can.”

While the Celtics boast a clear top six that is probably the best in the league, there are going to be plenty of nights when they need some bench players to step up and fill a role. The first example came Friday with Brissett. His playing time – as well as the rest of Boston’s depth pieces – may fluctuate throughout the season, but they’re embracing their position.

Having those players like Brissett who understand and thrive in their role as complimentary pieces to the stars is vital for a team with championship aspirations. That’s especially so for a Celtics team that underwent some turnover on their bench this offseason and is still in the process of carving out their rotation and identifying the depth players they can trust for the long run.

“We know that we’re going to be important throughout a lot of these games of the season,” Brissett said. “And then when it comes to playoff time, we’re going to be relied on, even if it’s for a little bit. Just go in there and just do what we do and do what we’ve learned all of training camp. …

“I feel like for anybody it’s tough. Like we all want to hoop, we all think we should be out there. But this is a winning team. You gotta put all that stuff aside, man, and really think about the big picture. So if I’m on the bench, I’m gonna cheer the guys on. If I’m on the court, I’m gonna do what I do. …

“But every night, I go in there expecting to play, wanting to play and approaching it like I’m going to play because you can get thrown in anytime. You don’t want to mess up. It’s quick, you might be out. So, just having that mindset in the right positive way, I feel that would help anybody in my position.”