Celtics fans target Kyrie Irving early and often in Game 2

Kyrie Irving (right) was hounded by the fans, and Al Horford, in the first quarter.Jim Davis/Globe Staff

The roles have been defined for decades. Spectators watch. Players play. Only recently has there been much interaction between the two. And it’s almost never good.

Brooklyn superstar Kevin Durant gave voice to it last spring while the Nets were in the process of wiping out the Celtics in a five-game playoff series.

“When you come to these games, you’ve got to realize these men are human,’’ Durant said after a TD Garden nitwit threw a water bottle at Kyrie Irving. “We’re not animals. We’re not in the circus. You coming to the game is not all about you as a fan. Have some respect for the human beings, and have some respect for yourself. Your mother wouldn’t be proud of you throwing water bottles at basketball players . . . "

Sunday during Game 1 of this highly anticipated Celtics-Nets first round series, Irving absorbed a lot of verbal abuse from Boston fans and made a decision to fire back. He flashed his middle finger at the Garden throng multiple times. When he was taunted backstage — on his way to the locker room — he responded, escalating the obscene dialogue. He was supported by teammates and a significant portion of the national media, but the NBA fined him $50,000 for his behavior.

Before Game 2 Wednesday, a 114-107 Celtics’ victory, coach Ime Udoka pondered the topic of fan-player interaction at NBA games.

“Talk and talk back,’’ said the coach. “When you say things now you are caught on camera. Obviously, there is back and forth. Say what you want, but know there will be some repercussions.’’

We’ve seen a lot of it in the last couple of playoff springs. Fans regularly hurl vile insults. Words you never heard in the Bible.

Last spring we had fans in Utah heaping abuse on the family of Memphis’s Ja Morant. We had fans in Philadelphia spilling popcorn on Washington’s Russell Westbrook. Now players are starting to answer. Charlotte’s Miles Bridges chucked his mouthpiece at a fan after getting ejected in Atlanta. Kyrie flipped the bird in Boston.

Former Celtics great Cedric Maxwell had some thoughts on the fan-player behavior trends.

“You can’t expect a guy to be yelled at for three hours by 18,000 people and not react,’’ said Max, who once went into the stands in Philadelphia to confront a 76ers fan who shouted a racial epithet. “In Kyrie’s case he got a little redundant on Sunday. Once, maybe. But three or four times? I think that’s where maybe Kyrie went over the line.’’

Red Sox fans chanted “[expletive] Kyrie!” at Fenway Monday night and there was plenty of suggestive signage in the Garden crowd early Wednesday evening. One fan wore a Kyrie clown-nose jersey, similar to the Roger Goodell bozo model worn after Deflategate. The Celtics Wednesday peppered their ticket-holders with pregame messages about the fan code of conduct.

Irving caught the opening tip and the first “Kyrie sucks!” chant erupted 17 seconds later. Not joining the chorus was Kyrie’s college coach, Mike Krzyzewski, who had Jayson Tatum, Seth Curry, and Irving at Duke. Krzyzewski also coached a couple of sons of Celtics co-owner Steve Pagliuca.

While fans were hooting on Irving, Dorchester’s Bruce Brown scored the game’s first 9 points forcing a Celtics timeout less than three minutes into the game. Kyrie’s first shot clanged off the back of the rim, much to the delight of the Garden gang. The first “[expletive] Kyrie” noise game with 7:38 left in the first and the Nets leading, 11-4. Near the Brooklyn bench, a member of the Nets’ staff could be seen speaking with a Garden security official. A uniformed police officer sat in the second row of the Nets bench, alongside Brooklyn coaches. Late in the quarter, there was an announcement warning fans to behave.

Irving had 39 points in Sunday’s 1-point loss in Boston. He scored only 2 in the first quarter of Game 2, but Brooklyn led, 33-24, after one. A jumper by Irving early in the second pushed the visitors to a 45-31 lead and forced a Boston timeout.

Observing Ramadan, Irving can’t eat until sundown, and he took a break during the first half to go back to the locker room to grab a banana. His teammates more than picked up the slack, running to a 17-point lead. Brooklyn led, 65-55, at intermission and the Celtics were lucky it was as close as it was.

The Celtics got back in the game by doing what they’ve done best in this series — forcing turnovers. It seems like every time Durant brings the ball down, quick Celtics hands pick his pocket.

The Celtics clawed all the way back and tied it, 79-79, on a bucket by Daniel Theis after Derrick White blocked Irving. Then Durant went to the bench with his fourth foul. He finished with 27 points but shot just 4 of 17 as the Celtics outscored the Nets, 59-42, in the second half.

And Irving was mostly silent in Game 2. He had 10 points and shot just 4 of 13.

The Celtics didn’t need another fantastic finish.