With Mikel Brown Jr. and Egor Dëmin leading a pack of seven first-round draft picks the past two years, the Nets were always going to suffer growing pains. 

There was plenty of pain and suffering in Tuesday night’s heartbreaker in Boston. 

And the Nets hope for plenty of growth down the line. 

Brown, the No. 6 overall pick, had what should have been a breakout moment in a thrilling victory in Boston. He poured in 13 points in a fourth-quarter Nets comeback, including a clutch 3-pointer with three-tenths of a second left to force overtime. 

But it was in that dramatic extra stanza that Brown made a pair of typical rookie mistakes, mental gaffes on each end of the floor that will be galling today but growth opportunities for tomorrow. 

“[Jordi Fernández] obviously acknowledged, ‘This wasn’t just on you. It’s a team effort.’ But I set standards for myself when it comes to that stuff,” the 20-year-old Brown said. “As a guard, time management, blowing coverages on the defensive end, that I just can’t have. I’m gonna go watch that film with the coaches, go watch film with Jordi, break it down, learn from it and be better.” 

Much of the film won’t be fun. But it may end up being fruitful. 

It will show Brown’s 17 points, five assists and five boards in his best game yet. 

But it will show the time-management mistake, when Brown missed a pair of late layup attempts in overtime, the second of which was ill-advised. 

He should’ve pulled the ball out and bled the clock. But he drove and missed with 2.3 seconds left in overtime to give Boston one last chance. 

“It was discussed to just try to get it in, and try to kill time. That definitely was discussed,” Brown acknowledged. “But like I said, man, it’s just mistakes down the stretch that I just can’t make. I just can’t do that, so …” 

It proved a costly mistake. 

Though Dëmin pointed out it was not purely a rookie one, citing De’Aaron Fox’s similar NBA Finals Game 4 call to go for a layup rather than run the clock that cost the Spurs. 

“Listen, I don’t think it’s a good idea to refer to him being a rookie. That happens to anybody. We saw in the Finals something similar happened,” said Dëmin. “I don’t think anybody should be taking blame for that. It’s a team effort and team results. So, there’s so many things we can learn from not just this game, but any game. It’s a great, great experience to have games like this. As many games as we can play where it’s a close ending, that’s gonna be beneficial for us in the future.” 

Brown will be a huge part of that future. And he’ll take lessons from games like Tuesday, taking responsibility on X. 

After missing the layup, his gaffe on the other end set up the winner. 

The Nets weren’t supposed to switch, intent on using Noah Clowney’s length to defend Jayson Tatum. But when Brown got screened, the rookie switched and let the Celtics star end up on a smaller defender. 

The Nets paid, as Tatum hit a midrange winner that beat the buzzer. 

“We were supposed to stay home, especially on Tatum, keep Noah on Tatum. I got caught up because I didn’t know which way Payton [Pritchard] was gonna go, and we ended up switching,” said Brown. “So, completely put the blame on myself. I can’t just break the coverage like that. I just take full accountability of it. It’s gonna be hard watching the film, and I’m just gonna learn from it.” 

After Brown had just one point through three quarters — on 0-for-5 shooting — he erupted for 13 in the fourth on 4-for-6 from the floor and 3-for-4 from deep. 

Maybe fatigued from logging a career-high 27 minutes, Brown was 1-for-4 from behind the arc in overtime. Instinct says get to the rim. In this instance, tactics and discipline had to override instinct. 

It’s a lesson Brown will learn. And be better for.