Brooklyn wasted a great trip from Irving and watched Tatum steal Game 1 of this first round series that looked more like Game 7 of a final conference. Tatum’s cutting layout – with Irving defending him – just beat the final buzzer and beat the Nets 115-114 before a 19,156 crowd shook and shook TD Garden. Irving was completely unguarded on his return to Boston, scoring 18 of the game’s 39 points in the fourth quarter. And after rejecting the fans many times, the Nets turned the 15-point deficit in the third quarter into a three-point lead with 45.9 seconds left – one they could not hold. Irving – who gave the finger to the fans after a three-pointer with 2:18 remaining in the third – scored another 3 to make it 114-111 in the last minute. But Jalen Brown’s layoff reduced the lead to one and Kevin Durand (23 points, but 9-to-24 shots and six rebounds) lost a possible dagger 3. Tatum (31 points from the highest team) did the rest, taking a pass from Marcus Smart and stealthily entering for the winner of the match. Celtics forward Jason Tatum celebrates the basket that wins the game as Nets guard Kyrie Irving looks on. Getty Images Celtics striker Jason Tatum hits buzzer.NBAE match winner via Getty Images The project drove the crowd into a frenzy and the building trembled – the same crowd that Irving had apparently fed, sending their bile back one bucket after another. And a greeting with a double finger behind his head and cursing a fan who insulted him when he entered the locker room at half time. “It’s the same energy they had for me, and I’ll have the same energy for them,” Irving said. “And he is not every fan. I do not want to attack every Boston fan. But when people start shouting p – sy, and b – ch and f – k you and all that stuff, there is only so much you can get as a competitor. And are we the ones who are expected to be submissive and humble and have a humble approach? Nah, that. “It’s the playoffs. This is what it is. I know what to expect in here, and it’s the same energy I give them back. It is what it is. I’m not really focused on that. It s funny. … Everything is fair to the competition. So, if someone is going to call me by my name, I will look them straight in the eye and see if they really do. “Most of the time it is not.” The Nets may have lost in the last game, but in many ways all 48 minutes showed their flaws, the Achilles heel of the season not so exposed but confirmed. Beaten on the boards. Struck in color. And struck when he counted. The Nets guard, Kairi Irving, receives a foul during game 1 against the Celtics. Charles Wenzelberg / New York Post The Nets outscored 43-29 and won 56-32, despite the absence of Celtics center Robert Williams III. Bruce Brown – a proud Boston – had declared after Tuesday night’s play-in victory that the Nets would benefit from facing Al Horford and Daniel Tace instead of the injured Williams. However, Brown finished with five points, five fouls and a worse game minus-13. Horford had 20 points, 15 rebounds and co-8. With the game tied at 63-all at the beginning of the third quarter, the Nets allowed nine consecutive points. Brooklyn was 15 points behind in the third and had to rally behind Irving, who was supplying energy, “Accept it. Accept it. It’s the dark side. Embrace it,” Irving said. “We know you will show up and support their team. But we know we will let Kyrie hear it as much as possible. So that’s what it is. “This is part of the sport,” said Durant, who saw the Celtics not even expect to double him, and struggled to look his best. “I feel like we turned it around – I had the most turnovers, six of them. That helps them get out of the break, you know. S – t, they also had 14 turnovers. I think the difference was probably, s – t, offensive rebounds. They beat us to a degree. It’s just a difficult loss, man. “It’s hard to find just one thing.”