The NBA fined Brooklyn star Kyrie Irving $50,000 on Tuesday for his repeated violation of the league's code of conduct during Game 1 of the Nets' first-round playoff series against the Boston Celtics.

Television cameras first caught Irving flashing his middle finger at the TD Garden crowd after a successful jump shot late in the third quarter. Video from a spectator inside the arena also showed Irving wrapping his hands behind his head and directing two middle fingers toward fans midway through the fourth quarter.

"The same energy they have for me, I'm going to have for them," Irving said following the game. "And it's not every fan. I don't want to attack every Boston fan, but when people start yelling "p****" and "b****" and "f*** you" and all of this, there's only so much you can take as a competitor. We're the ones expected to be docile and be humble and take a humble approach. No. F*** that. It's the playoffs. This is what it is."

Irving played two seasons for the Celtics. Prior to the 2018-19 season, he vowed to re-sign with them in front of a crowd of season-ticket holders, only to submit a haphazard playoff performance and leave for the Nets in 2019 free agency. When he returned to TD Garden for a first-round playoff series last year, Irving purposefully stomped on the Celtics' leprechaun logo at midcourt to punctuate a Game 4 victory.

Soon afterward, a fan thew a water bottle at Irving and earned a lifetime ban from the arena.

Prior to Sunday's game, Irving asked the Celtics and their fans for a truce. "I just hope we can move past my Boston era and just reflect on some of the highlights I left at TD Garden that they can replay," he said.

Fan footage captured Irving issuing an expletive toward a fan prior to Game 1. He once again wiped his feet on the logo during pregame warmups. Celtics fans responded by booing Irving each time he received the ball throughout the game and chanting "Kyrie sucks" as he attempted free throws in the third quarter.

Game 2 of the Nets-Celtics series is scheduled for 7 p.m. on Wednesday night in Boston.

Irving received a $381,181 fine from the Nets for each home game he missed this season for failing to meet New York City's COVID-19 vaccine mandate. Those penalties amounted to $14,103,697 before Mayor Eric Adams lifted the restrictions for professional athletes and performers in entertainment venues on March 24. The NBA also fined the Nets $50,000 for allowing Irving to join the team in the locker room on March 13.

In January, Irving earned a $25,000 fine from the league for telling Cavaliers fans who heckled him during a game, "Got y'all a championship and motherf***ers still ungrateful." He played for the Cavs from 2011-17.

Irving's fines this season are the second-most in NBA history behind only Nets teammate Ben Simmons, who was penalized almost $20 million by the Philadelphia 76ers for holding out following his trade request. Simmons reportedly filed a grievance in an attempt to recuperate his salary, citing mental health reasons.

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Ben Rohrbach is a staff writer for Yahoo Sports. Have a tip? Email him at rohrbach_ben@yahoo.com or follow him on Twitter! Follow @brohrbach