There’s a moment in the game when Avery Bradley knows he has done what he set out to accomplish. It happens when the man he’s guarding starts to talk to him. Sometimes he tells him to back off, give him some room. Other times he tell Bradley that he doesn’t have to pick up fullcourt all the time.

“When they start talking to me like that,” Bradley said. “That’s when I know I got them.”

How often does he hear it? 

“Everybody says it to me,” he said. “Everybody.”

And Bradley, well, he’s not much for talking back during the game. Instead he’ll just laugh and go back to doing what he was doing, which is making life a living hell for whatever unfortunate point guard has to bring the ball up the floor against him. Like Orlando’s Jameer Nelson. 

Bradley took the veteran former All-Star apart for 30 grueling minutes. He forced five turnovers, including an 8-second violation when Nelson couldn’t get the ball over halfcourt. After it was over and the Celtics held the Magic to a franchise-worst 56 points and an unconscionable 16-for-65 shooting in an 87-56 victory, everyone was talking about Bradley.

Kevin Garnett: “It’s very, very hard to do in this league against a player like Jameer Nelson.”

Jermaine O’Neal: “I think he’s one of the best on-ball defenders in the game and he does at it a very high level for an extended period of time. You don’t see that.”

Stan Van Gundy: “His defense set the whole tone for the entire thing. He took us out.” 

Doc Rivers: “That was the whole gameplan. The thing with them is you don’t want to give them a lot of clock. We were just trying to lower the clock as much as we could.” 

For good measure, Van Gundy added, “That’s the most dominating defensive performance I’ve ever had against me.”

This, in a nutshell, is what the Celtics think they are and what they think they can still be. After a dreadful start to the season, their defensive metrics have begun to creep back toward normalcy. They began the game ranked 10th in points allowed per 100 possessions and their defensive rebounding has also begun to climb back to respectability.

“We ain’t going to get much better than this defensively and I think it’s a good blueprint for them,” Rivers said. “But it also tells them how hard it is. It’s hard work. I mean Avery was dying out there. Two weeks ago we couldn’t have done this anyway because of conditioning. We would have never lasted.”

On a night when they didn’t have two starters and three more rotation players, the Celtics turned the Magic inside out, suffocating Dwight Howard and contesting every shot on the perimeter. Howard shot 4-for-15 and Ryan Anderson who has been setting the league on fire missed all eight of his shots.

That it came against one of the better teams in the league was not lost on the Celtics, either. They know their record and they know that up until Monday they had exactly zero wins against teams with winning records.

“You don’t want teams to come in here and feel like they can just beat you,” O’Neal said. “For the most part teams have had us on our heels. It’s time to switch gears and give them a feel for what the Celtics are about.” 

O’Neal gave Howard a feel for what the old Celtics were about after a play in which the two big men collided in the paint. O’Neal came back at Howard, wagging a finger in his face and the two had to be separated.

“Two big men, just having a nice little conversation,” Rivers joked. “That’s all I saw.”

It was more than that, of course. It was Howard’s elbows, long a point of contention with the Celtics and O’Neal decided that he had seen all of those that he was willing to take.

“He puts you in a compromising situation because he is really strong with his elbows and on the moves that he makes, he swings through with his elbows,” O’Neal said. “Sometimes you’re going to see guys get upset about that and sometimes you’re not. Tonight, I didn’t really like it too much.”

But the Celtics loved what O’Neal did. The much-maligned center didn’t score a point, but it didn’t matter. Judge him on his defense as he said last week -- and his defense has been very good -- but his reaction encapsulated all their frustrations that have been building through the first 15 games.

As Paul Pierce put it, O'Neal's reaction made it clear that, “We’re not taking this. You’re not going to throw your elbows in my face.”

It wasn’t just Bradley and O’Neal. It was Garnett who was a monster in 28 minutes, taking Anderson out of the game and even taking a turn on Howard when O’Neal got into foul trouble in the first half. Garnett played the last four a half minutes and allowed Howard to score just one point. The Celtics led 32-29 at the time and by halftime they had a 10-point advantage.

“He was the Kevin we know,” Rivers said.

This was the Celtics we know. It wasn’t a schedule win or a lockout game. The Magic have been off for two days and had everyone healthy. They had won seven of eight with the only loss coming in overtime against San Antonio. The Celtics were the ones on the second end of a back-to-back, missing two key starters.

“Everyone knew their assignments, and I can say for the first time in a long I think we carried out assignments to perfection,” Garnett said.

The rematch is on Thursday in Orlando and the players were already talking about being ready for payback because they know it’s coming.

There is much for them to prove, but as Van Gundy said before the game, “Now the Celtics are too old and can’t play at all. I’m not buying it. If that’s the story, that’s the story. You’re going to have to revise it when they win nine of ten.”