BROOKLYN — The murmurs grew from whispers, then to a dull roar as the obvious turned to reality, the chants turning into taunts at Barclays Center.

“Let’s go Celtics.”

Forty-eight minutes remain between the Brooklyn Nets meeting another premature end to what was expected to be a championship season, following a borderline soulless performance against the Boston Celtics.

Two championship players in the middle of their primes coming together was supposed to result in something dynastic. Instead, the team facing the most pressure in arguably the NBA’s modern-day history sat on a whoopee cushion and laid an egg.

The Celtics smelled blood after expecting to take the Nets’ best shot, then settled themselves to pull off a road win on a night where their best players grinded themselves to having a good night.

The Nets’ best players were aimlessly wandering in the wilderness, thinking and overthinking, creating the feeling that the basketball gods and karma were somehow working against them. Kevin Durant took fewer shots than Bruce Brown, a solid player but one nobody in Celtics green feared. In fact, it was probably in Ime Udoka’s master plan to have Durant confused with what he saw, turning him into a stationary target rather than the sniper he’s been for the last decade or so.

“I probably should’ve took more shots,” Durant confessed. “But I tried to play the game the right way without being too aggressive. I’m just thinking too much this whole series, to be honest.”

This wasn’t some punishment by outside forces, it wasn’t Durant’s foot barely touching paint in a Game 7 against an eventual champion. The only similarity between the last playoff and this one was the opponent being fortified by true failure and a genuine respect for the process of 82 games.

It’s borderline amazing how Durant could operate at full functionality and usurp everything in Golden State’s championship culture, yet bring none of it with him — or not know how to foster such an environment.

He couldn’t help himself, didn’t have the system or support from the bench either. If there’s one quality of any NBA player that felt like a sure thing, it’s Durant as a scorer, doing it easily and better than perhaps anyone we’ve ever seen.

He’s not a system, nor does he belong to one. The beauty in Durant is that he can operate anywhere, any time and be himself. But one of the surer playoff performers of all time isn’t living up to that, and it doesn’t appear likely some miraculous strategic alteration will give the Nets some experience they lack in order to aid him.

His co-star has been wholly unreliable for one reason or another, and it’s hard to envision this being a championship outfit with the evidence placed in front of us. Even the addition of Ben Simmons likely wouldn’t have changed this outcome. Does Durant order the code red this offseason when Kyrie Irving will undoubtedly ask for a full max extension? Or will the Nets front office assert itself and take control of the franchise for the betterment of the franchise, and the betterment of Durant’s remaining prime?

It’s either being allowed or encouraged, and there’s no sign the lack of commitment is met with real pushback, real leadership. And even then, the East is too good to have this incomplete of a roster — even if Durant remains the baddest man alive save for these three bad games.

Newly minted Defensive Player of the Year Marcus Smart remarked on the Celtics’ journey earlier in the day, referencing how poorly the team was playing early in the season and how they had to dig themselves out of a self-inflicted hole, emboldened by the lessons learned.

Now, they’re teaching the Nets with one hard knock after another — merely by playing hard for longer stretches and better than their opponent.

It sounds simple enough, but it’s contrasted by Nets coach Steve Nash saying over the last couple of days that his team is still learning each other as opposed to putting that knowledge to use when the games matter the most.

Nash will take his lumps, being schooled by Udoka in terms of X’s and O’s, but Udoka turned his season around by calling out his best players, perhaps risking unbuilt equity in the moment. Udoka’s play worked, while Nash has perhaps tiptoed around his stars — players he once competed against on the back end of his career. It doesn’t seem easy to assert authority when the Nets’ power structure is as such: Durant and Irving’s role in bringing him in, along with their sentiments of not truly needing coaching.

What hammer can he wield then? And history says he’s certainly on his way to yet another playoff disappointment with a generational player and a total of one playoff series win to show for two years coaching.

The Nets lack size and length, having to dust off Blake Griffin, who hasn’t played meaningful minutes since February, to give them a spark in the second half. After he hit a shot or dove on the floor to preserve a possession, the Celtics hunted him on the other end and succeeded.

“I don’t think our spirit was right tonight,” Griffin said, likely alluding to the lack of desperate energy his team displayed.

Durant and Irving ditched the big stage of Madison Square Garden for hipster Brooklyn, stating they wanted to build their own tradition instead of latching onto decades of Knicks failures.

Noble enough, but building tradition requires investment, and sweat equity, and attendance. So far, Irving has been truant when his presence has been called upon, placing more pressure on Durant to do and be everything.

They showed up for a first date and forgot their wallet — all that’s left is deciding who’s busting suds in the back.

“We’re all trying to jell and usually you’re jelling around the right time,” Irving said. “And that team in the other locker room is jelling at the right time, been jelling since Christmas. We’re just in a new experience as a group, and we have to respect that.”

Ahh, Christmas. When the Nets still employed James Harden and Irving was still away, by virtue of being unvaccinated and weeks away from being allowed back out of desperation when bodies kept getting infected by the Omicron COVID-19 variant.

That’s when the Celtics — who brought in rotation players Daniel Theis and Derrick White at the deadline, contributors in this three-game destruction — started to figure things out. They had Jayson Tatum, Jaylen Brown and Smart as anchors who were still growing and maturing to aid in the transitions of any new pieces.

Durant would soon be out with a knee injury. Irving would be headed in and out the door before being granted clemency by New York City Mayor Eric Adams, but looked like a player who wasn’t used to playing basketball consistently enough to work through the flows of fatigue or even the familiarity of teammates’ tendencies.

Say what you will about Nash, but he had very little evidence of what his team looked like together before running into this buzzsaw. And you know what would’ve helped? An actual point guard, a leader on the floor.

Irving came close to accountability in the small picture, but didn’t dare venture to the macro.

“I don’t have a lot of answers for how you make up time from October until now,” Irving said. “When teams would be jelling and playing good. You know, you could put it on me in terms of playing better, controlling the game better, controlling our possessions … not turning the ball over as much.”

The Celtics defense is real, so there’s only so much room to blame Irving for a bad night. But the position the Nets are in — their stars playing heavy minutes, looking unfamiliar at times, fatigued in others — can be traced back to Irving.

“They both gotta be tired,” Nash admitted, even though Durant would have none of it when asked later. “Kyrie’s fasting [for Ramadan] and Kevin’s had to play 40-plus minutes for five, six weeks after missing six, seven weeks. We need him to play 40 minutes so we could be in the playoffs.”

The Nets have been playing catch-up all year, looking over the edge before barely pulling themselves back from the brink. It only took a little noise in their home building to push them right back to the point of no return, and it echoed louder and louder through the night.

“Let’s go Celtics.”