The Boston Celtics opened up to full capacity just in time for the local fans to jeer and swear - and worse - at Kyrie Irving as he helped his side to a 141-126 NBA play-offs win.
Irving had 39 points and 11 rebounds to quiet the first post-pandemic full house at the TD Garden but as he left the court he was nearly hit by a bottle thrown from the stands - with reports that police led out a man, wearing a Kevin Garnett jersey, in handcuffs.
The incident came just days after a Philadelphia fan threw popcorn at Washington guard Russell Westbrook.
Irving said he didn't think banning or even arresting unruly fans would solve the problem, ascribing it to "underlying racism and treating people like they're in a human zoo".
"People feel very entitled out here," said Irving, who played for the Celtics from 2017-19 and said last week he experienced racism during his time in the city.
"As a black man playing in the NBA, dealing with a lot of this stuff, it's fairly difficult...
"It's just unacceptable for that stuff to be happening. But we move on."
Kevin Durant led all scorers with 42 points while James Harden added 23 points and a career postseason-high 18 assists for Brooklyn.
"Fans have got to grow up at some point... We're not animals. We're not in the circus," Durant said.
Game 5 is in Brooklyn on Tuesday night, when the Nets will try to advance to the Eastern Conference semi-finals for the first time since 2014.
Earlier on Sunday, Chris Paul shrugged off a shoulder injury to drive the Phoenix Suns to a 100-92 win over the Los Angeles Lakers which levelled their first-round series at 2-2.
The home loss was not the worst news for the Lakers, after All-Star big man Anthony Davis sustained a groin injury late in the second quarter and did not return to the game for the defending champions.
The Los Angeles Clippers won in Dallas for the second time in as many games, this time 106-81 over the Mavericks to level their western conference showdown at 2-2.
Meanwhile, the Atlanta Hawks cruised past the New York Knicks 113-96 to take a 3-1 lead in their eastern conference series.
Suns coach Monty Williams initially planned to sit Suns veteran Paul for Sunday's game but the 36-year-old proved he can still contribute despite being limited physically, netting 18 points and dishing out nine assists.
"I told them, 'I don't know how long it's going to be, but if you all feel like I'm out here looking like some trash, just tell me and I'll get out'," 11-time All-Star Paul said.
Not even LeBron James - who had 25 points and 12 rebounds, could save the Lakers this time with Davis' absence from the second half contributing to the Suns reclaiming home-court advantage in the series.