James Harden had 22 points and 10 rebounds for Brooklyn, which improved to 25-13 with its 12th win in 13 games. Landry Shamet added 18 points and fellow reserve Jeff Green finished with 11. Joe Harris added 12 as the Nets won without Kevin Durant and newcomer Blake Griffin.
''We have a multitude of guys who can take us home and carry it out, and we trust in them,'' Shamet said. ''It's just a matter of us putting an entire game together and putting us in the best position possible.''
''That's a really good team,'' Tatum said. ''A couple of us didn't shoot it well so obviously there's some things we could do better.''
The first meeting between the Atlantic Division rivals since Christmas emphasized the gulf between the teams - specifically, Brooklyn's quick strike offense.
The Nets began the fourth with an 88-86 lead, but it took just more than 3 minutes to extend the advantage to 100-90 even as Irving sat on the bench.
After Boston cut the lead to five following Tatum's jumper, Irving and Harris checked back into the game and the Nets promptly outscored Boston 21-14 for the remainder of the game. In that 7:34 stretch, Irving made two 3s and two free throws against his former team, and when Green slammed a two-handed dunk with 43 seconds left, the outcome was basically decided.
''That's what makes the game beautiful,'' Irving said. ''Being able to have spurts. It's just the flow of the game. When it gets to that quarter, when it's winning time, I've always said it throughout my career I enjoy it more than anything else.''
Smart had missed 19 games dating back to Jan. 30 with a strained left calf. He played 21 minutes after Boston coach Brad Stevens said before the game that the guard would be limited to 20-22.
How did the Celtics settle upon that time frame? ''What I do is I get told and I follow instructions,'' Stevens deadpanned. ''It's a lot like being married, right? My wife tells me what to do and I do what she says. That's pretty much how this all works with the minute restrictions.''
CELTICS: Boston began the second half in fourth place, just a half-game up on the surprising New York Knicks. But that does not mean Stevens is publicly lobbying GM Danny Ainge to be active in the trade market. ''I coach the team, right,'' Stevens said. ''My job with the guys that are here, to help them be the best that they can be and hopefully put them in a position to succeed individually and collectively. Sometimes that takes time to figure out how that all fits together. Sometimes that takes time for people to impact the way they're best able to. That's my task. My task is to put the puzzle together that is on our roster.''
NETS: The Nets announced Wednesday that Durant would not play due to an injured hamstring, the 10th straight game he has missed. Griffin, who signed Monday, did not play against Boston due to the fact Detroit deactivated him beginning on Feb. 12 in an attempt to trade him. before making the decision to buy out the former All-Star. ''Everyone's excited to have him,'' Nets coach Steve Nash said before the game. ''We'll see how he can impact our team. He's a talented, intelligent player.''
CELTICS: Travel to Houston on Subday night.
NETS: Host Detroit on Saturday night.
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