Celtics forward Jayson Tatum celebrates after making a layup at...

Celtics forward Jayson Tatum celebrates after making a layup at the buzzer to score and end Game 1 of an NBA first-round Eastern Conference playoff series against the Nets on Sunday in Boston. Credit: AP/Steven Senne

BOSTON — Kyrie Irving had piled up his points, and made his point with multiple obscene gestures to the crowd. But in the end, it was Jayson Tatum and the Celtics who got the last word.

Irving had taken over the game, scoring 39 points — 24 in the second half — as the TD Garden crowd loudly booed and taunted him during pregame introductions and every time he touched the ball. He had answered every one of those chants and appeared to lift the Nets to a comeback victory.

It wasn’t the fans or Irving who would get the last word, though. With the clock ticking down to its final tenths of a second, Marcus Smart found Jayson Tatum cutting to the basket. Tatum spun around Irving and banked in a layup as time expired to give the Celtics a 115-114 victory in Game 1 of the best-of-seven first-round playoff series.

The game, the atmosphere and the stars lived up to the hype that preceded this series as the second-seeded Celtics faced off against the seventh-seeded Nets, who had struggled just to reach the playoffs but still entered as one of the most feared contenders for the title.

As great as the game was and as dominant as Irving was, it was hard to ignore the fans, and he didn’t. The fines certainly will be coming for him, but he wasn’t apologizing.

“Where I’m from, I’m used to all these antics and people being close nearby, it’s nothing new,” Irving said. “When I come into this building what it’s going to be like, but it’s the same energy they had for me, and I’m [going to] have the same energy for them.

“And it’s not every fan. I don’t want to attack every Boston fan, but when people start yelling [expletives] and all this other stuff, there’s only but so much you can take as a competitor. And we’re the ones expected to be docile and be humble and take a humble approach. Nah, [expletive] that. It’s the playoffs. This is what it is. I know what to expect in here, and it’s the same energy I’m giving back to them.”

Irving had appeared to get the best of a crowd that had it in for him from the pregame introductions on, helping the Nets overcome a 15-point second-half deficit (it was 11 entering the fourth quarter). He scored 18 points in the final quarter, shooting 7-for-9, including 4-for-5 from beyond the arc. The last shot — a three-pointer with 45.9 seconds to play — appeared to be the dagger, giving the Nets a 114-111 lead.

Jaylen Brown pulled Boston within one with a quick layup, and this time the Celtics worked to get the ball out of Irving’s hand, smothering him with multiple defenders. Kevin Durant, who shot 9-for-24, misfired from long range with 15 seconds left and the Celtics rebounded.

Rather than call time, Boston coach Ime Udoka let his team play. The Celtics rushed the ball upcourt and swung the ball around — with each player touching it — until Smart split defenders, passed on a jumper and found Tatum, who spun to the rim past Irving as time expired.

“We talked about staying poised, being able to move on,” Boston’s Al Horford said. “At that point, a team can go one of two ways, and we got a pretty good handle of the game in the third and it kind of just got away from us. Just give our group a lot of credit because we all understood that we needed to stay with it.

“That was the biggest thing: Stay with it no matter what and continue to play. And that’s what we did.”

It set off a wild celebration as the officials rushed to confirm that Tatum released the shot ahead of the buzzer.

Irving has insisted that he has no hostility toward the Celtics — one season after he stomped on the leprechaun at midcourt and dodged a water bottle thrown at him on his way out after the Nets beat Boston in Game 4 of last season’s first-round series.

“It is what it is,” Irving said. “I’m not really focused on it. It’s fun, you know what I’m saying? But where I’m from, I’ve dealt with so much, coming in here, you relish it as a competitor. And I’m [going to] keep repeating myself when I say it again, but this isn’t my first time in TD Garden, so what you guys saw and what you guys think is entertainment, or the fans think is entertainment, all is fair in competition.

“So if somebody’s going to call me out of my name, I’m [going to] look at them straight in the eye and see if they’re really about it. Most of the time they’re not.”

It likely won’t change for Irving in Game 2. He isn’t asking for it to change. “Embrace it,” he said. “Embrace it. It’s the dark side. Embrace it.”

Kyrie Irving’s fourth-quarter heroics came up just short. Breaking down his shot-making in Game 1:

Points FG-FGA.

First Quarter 4 0-2

Second Quarter 11 3-4

Third Quarter 6 2-5

Fourth Quarter 18 7-9

Totals 39 12-20

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