Boston forward Jayson Tatum is defended by Brooklyn guard Kyrie Irving during the Celtics’ 104-93 loss in Game 1 of their first-round playoff series on Saturday in New York. Corey Sipkin/Associated Press

NEW YORK — For all their faults, errors and miscues, the Celtics looked like they could still steal a game midway through the fourth quarter. They were only down three points to the Nets with 7:27 left, more than enough time to snatch a victory.

This was the defensive blueprint the Celtics created in preparation for the Nets. While there was some luck involved in the first half – the Nets were 1 for 13 on 3-pointers – Boston was clearly making Brooklyn uncomfortable. The Celtics looked spirited, locked in, communicative – and they were rewarded with a solid defensive night against the best offense in the NBA.

All of those efforts were for naught as the Celtics’ offense faltered down the stretch. It wasn’t one player or a few shots that doomed them; it was a whole-game effort, aside from one quarter. The Celtics scored 32 points in the second, their best 12-minute stretch, but managed 21, 20 and 20 points in the other quarters.

While on paper the first-round Celtics-Nets series pointed toward a shootout, it was the opposite end result. Boston defended at a high level, but it wasn’t enough to overcome a sluggish offense in a 104-93 loss Saturday at Barclays Center.

“We held them to 104, and I know they missed some opportunities, but our guys really guarded,” Celtics Coach Brad Stevens said. “What we said all week was: scoring in the 90s isn’t going to be good enough. And we’ve gotta do a better job of attacking them with all the switching and being a little bit more purposeful than that.”

The Nets finished 35 for 84 from the field, which translates to 41.7%. The No. 1 offense in the league shot worse than that only six times during the regular season, and the Nets were 1-5 in those games. Yet Brooklyn still prevailed Saturday. Their superstar trio of James Harden, Kevin Durant and Kyrie Irving combined for 82 points, but they’re expected to get their production.

The Celtics went ice-cold – especially with the game still in flux. They shot 36.9% from the field, cooling on 3-pointers while the buckets refused to drop. After the Celtics cut the Nets’ lead to three points in the fourth, they only mustered three points over the next 5 minutes, 27 seconds. By then, Brooklyn surged to a 17-point lead.

“It’s the playoffs, man,” Marcus Smart said. “If you aren’t going to bring it, you might as well stay home. All you can do is control what you can control. … We did pretty good. Obviously, we had a couple breakdowns that we’ll see in film tomorrow. We’ll fix it and see what we have to do and come out and try to execute it again.”

Boston endured brutal shooting efforts from the guys it needed to score. Jayson Tatum hit his first three field goals, but finished 6-for-20 overall and didn’t make another field goal in the first half.

Kemba Walker was 5 for 16 for 15 points as he was bogged down by foul trouble. Evan Fournier had 10 points but it was on 3-for-10 shooting.

The unlikely hero was Smart, who hit huge buckets when the Celtics needed it. A jump shot in the third quarter – after the Nets jumped out to a nine-point lead – kept the Celtics in the game and quieted the sold-out crowd of 14,391 fans. Smart finished with 15 points, but the Celtics’ offensive execution as a team lacked.

“Pick your spots,” Tatum said of the offense. “Be precise. Obviously, we’re not going to play perfect, but make the right pass, make the right play. You’ve got to be quick, obviously, when they’re loading up and helping, whatever it is. You can’t relax. You’ve got to go quick.”

It was a stark difference on the court between the Nets and Celtics. Boston ran out to an early 12-point lead, controlling the pace of the game. Tatum was outplaying the Nets’ stars as he had a solid start. But when the shots fell for the Nets and not for the Celtics, Boston didn’t have enough answers.

Well, the Celtics’ normal response was at Saturday’s game, but Jaylen Brown was in street clothes, cheering on his teammates from the sidelines. While the Nets took turns in the third quarter picking between which of their talented stars would score, the Celtics could only watch from afar, all while bricking shots.

“We gotta just continue to play,” Smart said. “We’ve got to be strategic and optimistic on the fast breaks and transition. You’ve just got to continue to make them work on both ends of the floor. They’re going to go down and make some tough shots on the offensive end; you’ve got to make it even tougher for them on the defensive end.”

Playoff series are, of course, all about adjustments from game-to-game. The Celtics — and Stevens in particular — have years of experience when it comes to game preparation. Boston had the necessary game plan Saturday, at least on one end of the floor.

But the Nets will adjust, whether that’s to Robert Williams III stellar athleticism or elsewhere. But so will the Celtics, which Stevens reaffirmed with conviction.

“We got another couple days to get ready for Game 2,” Stevens said. “That’s gonna be really intense. But hey, our guys are ready to compete and we’ll look forward to that. And we’ll be better. We’ll attack them better.”