BOSTON -- With the Celtics leading by 17 points at the end of the third quarter Tuesday night, Brooklyn Nets guard Caris LeVert wasn't even sure he'd get a chance to play in the fourth.

"I thought [Nets coach Kenny Atkinson] was going to pull [me], too," LeVert said. "[But] he put me back in there, so I just made one more run at it."

Did he ever.

By the time the dust had settled, not only had the Nets erased that deficit, LeVert -- who had scored 14 points through the first three quarters and taken just 10 shots -- had outscored the Celtics 37-36 by himself over the course of the fourth quarter and overtime to produce a stunning 129-120 win in front of a sellout crowd at TD Garden.

LeVert finished with a career-high 51 points, making him the second Nets player to have a 50-point game this season, joining Kyrie Irving. No player in the past 20 seasons has scored more than LeVert's 37 in the fourth quarter and overtime.

"It's really hard to even comment," Nets coach Kenny Atkinson said afterward. "I'm still trying to process it all."

He wasn't the only one.

The story of this game began in the fourth quarter, which started with the Nets playing three little-used bench players -- Chris Chiozza, Timothe Luwawu-Cabarrot and Rodions Kurucs -- with LeVert and DeAndre Jordan.

But it wasn't long before LeVert -- who scored 26 of his team's 51 fourth-quarter points, including burying three free throws with 0.2 seconds left to ensure the game would go to overtime -- got cooking. He finished the fourth going 7-for-10 from the floor, including 4-for-6 from 3-point range, and 8-for-11 from the foul line, as well as assisting on three of the other eight made field goals Brooklyn had during the quarter.

"He [wasn't] missing," Luwawu-Cabarrot, who finished with 16 points and eight rebounds himself, said of LeVert. "He couldn't be stopped.

"When you've got a guy like that, it's easy. You play defense, give him the ball on offense, and do what you have to do."

Still, for all of LeVert's brilliance, the Celtics provided him and the rest of the Nets plenty of help. Brooklyn shot 15-for-23 as a team in the fourth quarter while also pulling down seven offensive rebounds. The Nets were able to overcome a 17-point deficit while the Celtics still shot 50% (10-for-20) from the floor and scored 34 points themselves.

The Nets' 51 points are the most the Celtics have allowed in a quarter since February 1970, when the San Diego Rockets scored 54 in the fourth.

"We didn't have any defensive intensity," Celtics coach Brad Stevens said. "I should have subbed a couple of guys out that normally play, and I just kept them in.

"We had the right intensity for most of the game and we just let our foot off the gas. But we got four stops in the fourth quarter. They scored 51 points. ... We made a lot of plays today that were just not winning plays --and very simple, basic parts of our defensive system.

"But they deserved to win. I guess if you're in this game long enough you'll see it at some point. And we saw it tonight."

Meanwhile, the Celtics committed multiple gaffes in the closing seconds. Rookie Grant Williams nearly committed an inbounds violation before calling timeout. Then, on the ensuing inbounds play, Kurucs tied up Kemba Walker, forcing a jump ball that was easily won by Kurucs, who is nearly a foot taller.

That gave the ball back to Brooklyn, trailing by three, with 1.4 seconds left. After the ball was inbounded to LeVert, he was fouled while shooting a 3 by Marcus Smart with 0.2 seconds left, giving himself the chance to tie the score at the line.

"Never have I ever before," LeVert said when asked afterward if he'd ever been in that position. "That was very unique, but I was confident when I stepped onto the line that I was going to hit all three."

He was right -- and, as a result, the game went to overtime.

From there, it was clear before long Brooklyn was going to close this out. Having already lost Gordon Hayward (knee) and Jaylen Brown (hamstring) to injury during the game, and with Jayson Tatum already sidelined by an illness, the Celtics then found themselves without Walker -- who hit his minutes limit in his return from left knee soreness at the end of regulation -- in overtime.

Then, shortly after overtime began, Smart fouled out, and Boston was without all five of its top perimeter players. As a result, LeVert was easily the standout player on the court, and he played like it. He scored all 11 of Brooklyn's points in overtime, with only rookie Carsen Edwards managing to hit one pull-up jumper for Boston.

Smart was very upset with the officials afterward, and Celtics security had to steer him back toward Boston's locker room. Smart didn't speak to reporters after the game.

No matter Smart's frustrations, however, there were plenty more reasons why Boston lost -- none bigger than LeVert's masterful performance. He simply got whatever he wanted down the stretch and in overtime, including at one point hitting three straight 3-pointers in the fourth quarter.

Atkinson said he simply found himself trying to stay out of the way.

"It was all him," Atkinson said. "We didn't run anything, really. He just kind of took over. He called what's in our playbook, but I was definitely not calling plays.

"That's where as a coach you just have to get back [out of the way]."

It was a formula that led the Nets to a desperately needed win, one that snapped a four-game losing streak for a Brooklyn team still trying to hang on to one of the final two playoff spots in the Eastern Conference -- and on the same day one of the team's two tentpole stars, officially underwent season-ending arthroscopic surgery on his right shoulder. The other, Kevin Durant, tweeted after Tuesday's game about LeVert's performance, calling it "a masterpiece."

That 50 was beautiful, Vert. Thank you for that masterpiece

— Kevin Durant (@KDTrey5) March 4, 2020

On this night, though, LeVert more than made up for their collective absence.

"It was just play after play," Atkinson said. "He got a big deal, he obviously hit the three free throws at the end. ... It's just a miracle.

"It was just a classic performance. A very great performance."