How Sam Hauser and the Celtics bench have opened up the team’s offense

NEW YORK — After a record-setting night for the Celtics offense, Jayson Tatum and Sam Hauser went back and forth over a most important matter: Hauser’s 3-point celebrations.

Though Hauser said he’s not big on them most of the time, he apparently broke character once on Saturday night. After one of his four first-half 3-point makes, he cracked up Tatum with an over-the-top reaction. Following a quick postgame lift, Tatum asked Hauser to repeat what he had said after the shot.

“I said, ‘Boom, motherf—-r,’” Hauser replied.

He might need to find a new catchphrase. Tatum suggested that one doesn’t fit Hauser’s personality. Either way, the moment gave the two teammates plenty of laughs after a 133-118 win against the Knicks. And, hey, the line might even make sense as a motto for the Celtics, who continued a red-hot shooting start to the season with a franchise-record 27 3-pointers. All nine Boston players who appeared in the game drilled at least one triple, including Tatum, Hauser and Jaylen Brown, who combined for 17 makes. Early in this young season, the Celtics have used their abundance of shooters to stretch opposing defenses to their breaking point.

“I think that’s the thing with our team, right?” said Joe Mazzulla. “Because of our spacing we can get a really good look the majority of the time.”

At their best, that’s how the Celtics have played. After beating their previous record of 25 3-point makes with a 27-for-51 performance from long range, they top the NBA with an average of 16 3-point makes per game. Known more last season for their big, physical defense, they left Saturday night in a virtual tie with the Mavericks for the league lead in offensive efficiency. Lately, the second unit has charged some powerful runs thanks partly to Hauser’s emergence as another knockdown threat. The second-year pro, who only played 158 total minutes as a rookie, has made 17 of 31 3-point attempts so far this season (54.8 percent) while earning a bigger role. Mazzulla had a simple explanation for what Hauser has done to receive more minutes over the past couple of games.

“Shoot 3s,” Mazzulla said.

The coach stopped there for a second before eventually expanding on his reasoning.

“No, listen, he just plays the right way,” Mazzulla said. “He plays the right way, he knows how to play off the other guys, he can read defenses, he puts a lot of pressure on the defense. So it really helps our spacing. And he’s continuing to work at getting better at his defense.”

The Celtics have long relied on Tatum and Brown to give the nets a workout. The supporting cast around those two hasn’t always been filled with sharpshooters, but the team now boasts a second unit filled with outside threats. Lately, Mazzulla has turned up the offense by unleashing lineups with Tatum and three bench shooters: Hauser, Malcolm Brogdon and Grant Williams. Over 46 minutes with those four players on the court, the Celtics’ offense has…