While the effort may not be translating into consistent wins yet, it’s clear the Nets are improving. Tuesday’s matchup against the Boston Celtics marked the fourth straight game where Brooklyn’s competitiveness was never in doubt. But after almost 40 minutes of trading blows inside Barclays Center, Boston’s poise showed. The Celtics closed strong for a 113-99 win, sending the Nets to 2-12 despite Sunday’s high from beating Washington.

What made the collapse tougher to stomach was how well the Nets played for most of the night.

“I wasn’t happy with the way we were competing a few games ago,” head coach Jordi Fernández said. “And now, for four straight games, we’ve played a respectable brand of basketball, a competitive brand of basketball.”

Brooklyn came out firing, drilling four of its first five 3s and blitzing Boston with an 18-9 burst that had Barclays Center rocking. The Nets pushed the pace early, going 5-for-10 from deep and steamrolling the Celtics in transition with a 13-0 edge while building a lead that grew to 10. But the early cushion didn’t hold. As Brooklyn cooled, Boston kept scoring, shooting 52.6% in the opening frame. Payton Pritchard carved up the Nets for 11 quick points, dragging the game back to a 29-all tie after one.

The second quarter kept the same intensity. Michael Porter Jr. and Anfernee Simons traded buckets as both offenses maintained their rhythm, but Boston found just a little more separation. The Celtics hit 12-of-17 shots in the period and knocked down two more 3s than Brooklyn, enough to nudge them into halftime with a one-point lead despite the Nets shooting a strong 10-for-17.

And yet, even while trailing, Brooklyn turned the first half into a track meet. The Nets racked up 22 fast-break points, tied for their sixth most in any half since tracking began in 1997-98, sparked by 12 forced turnovers that kept Boston scrambling. Porter poured in 18 points before the break, while rookie Egor Demin caught fire, drilling all four of his 3s in his first 15 minutes to become the first Nets rookie since Rodions Kurucs to hit four triples without a miss in a half. With Demin navigating pressure, organizing sets and keeping the offense composed, Brooklyn shot a season-best 50% from deep in a half and punished nearly every Celtic mistake.

“We just keep working on the same thing every day,” Day’Ron Sharpe said. “Coach keeps preaching to us sticking to the plan, keep working at it and buying into what they’re trying to get us to do… We have to learn how to do it for 48 minutes.”

But the same third-quarter issues that have dragged the Nets all season resurfaced when Boston opened the period on a 13-4 run, pushing ahead 75-65 with 7:28 left and forcing a Brooklyn timeout. Again, the lead didn’t last. The Nets clawed back with sharp defense, holding Boston to 38.9% shooting and forcing five more turnovers, trimming the margin to four heading into the fourth quarter.

A Porter 3-pointer briefly put the Nets back in front with 9:08 remaining, but Boston immediately answered with an 8-0 run that rebuilt a seven-point cushion in a flash. Brooklyn never led again as the Celtics stretched the margin to double figures and stayed in control. Rookies Demin, Drake Powell, Nolan Traore and Danny Wolf finished the night as Fernández emptied his bench.

“We have a young team and we’re newly playing together, and I think [the Celtics] have been in so many situations in the fourth quarter as a group that they kind of knew how to execute down the stretch and we’re still figuring that out,” Porter said.

Despite shooting just 40.2% for the game, the Nets turned in one of their stronger defensive efforts, finishing with a season-high 12 steals. Porter led Brooklyn with 25 points, six rebounds and two assists, while Sharpe provided a lift off the bench with 16 points and seven rebounds.

Jaylen Brown paced Boston with 29 points, four rebounds and four assists.

The Nets won’t have to wait long for another shot at the Celtics. The teams meet again Friday at TD Garden.