Celtics give new Nets rude welcome

Two days ago, Kevin Garnett called the Brooklyn Nets a “force to be reckoned with.”

“Straight setup, OK?” Nets coach Avery Johnson said Thursday night after his team was waxed by KG’s Boston Celtics, 115-85, and suffered its first-ever preseason loss at the Barclays Center.

“If we are and we’ve gotten his attention, then he wanted to come out and play hard tonight. It was two different teams with two different agendas early in the game.”

As a result, right from the opening tip, it certainly felt an awful lot like the past three seasons. A smattering of boos could be heard midway through the third quarter inside the $1 billion arena.

Good thing this one doesn’t count in the standings.

“They came with an agenda tonight,” Johnson continued. “We were playing like it was a preseason game. Instead of having a ton of energy, we came out lethargic. But again, that team has a lot of pride, the Celtics, and Kevin Garnett came out tonight and [Rajon] Rondo and [Paul] Pierce with that look on their face like even though it’s a preseason game, we wanna send a message.

“I know that’s hard for a lot of people to believe in a preseason game, but that’s a true statement.”

The Celtics’ starters were upset that the Nets’ reserves had outplayed them on their home floor on Tuesday night. So they took their anger out on Brooklyn’s top unit in its brand-new building.

Thanks in large part to three Nets turnovers in the opening 76 seconds, Boston jumped out to a 9-0 lead -- and never looked back.

The Celtics shot a blistering 56.5 percent from the field, limiting Deron Williams (six turnovers) and Joe Johnson (4-for-14 shooting) to a combined 21 points.

Meanwhile, Garnett (14 points, 7-for-9 shooting), Pierce (18 points, 5 rebounds, 4-for-4 on 3-pointers) and Rondo (14 points, 9 assists) dominated.

“We weren’t too good tonight, but we needed a game like this against a good defensive team,” D-Will said in a statement. “We need to play better against a team like this.”

In the offseason, Williams was excited about Brooklyn’s chances to make a postseason run because they have a lot of overlooked players with chips on their shoulder. But on Thursday night, it was the five-time defending Atlantic Division champion Celtics that looked like they had something to prove.

“Nobody’s gonna jump off the bridge now, but it was a good learning lesson for us, and we got some good teaching points,” Avery Johnson said.

“They wanted to just come out and establish themselves and show that they’ve been successful in the last five years or so and that they’ve been successful for a reason.”

While the Celtics have proven themselves, the new-look Nets still have to learn how to become a cohesive unit both offensively and defensively. Then and only then can they be considered in the same class as the Bostons and Miamis of the Eastern Conference.

“And if there’s some supposedly new kid on the block -- you know how it is in the neighborhood -- you just want to show that it’s your neighborhood, and we’ve got to earn everything,” coach Johnson said.

“That’s the message this year: No matter what documentaries or books that are being written about us this year, everybody is not excited. Everybody is not impressed. So we’re gonna have to really play, and we can’t have that effort that we had early in the game.”