BOSTON – Heading into Game 3, there is one glaring area where the Celtics say they must return to form: defending the 3-point arc.

Such was their downfall in Game 2 Tuesday night, when the Miami Heat shot a playoff franchise-record 23-of-43 from deep, propelling them to a 111-101 series-splitting win.

It wasn’t just an anomaly for the Heat; it was also an unusual event for Boston, which led the Eastern Conference in 3-point defense during the regular season by allowing opponents to shoot just 35.2 percent.

However, Al Horford says there’s no room for such anomalies in the playoffs.

“You just have to be better,” he said Thursday before heading down to Miami for Game 3. “You have to be better defending the 3-point line. They shot a lot of them, a high frequency, and I know we will be better coming in the next game. There’ll be more of an awareness to that. And for us, defensively continuing to make sure that we do a good job of getting stops and holding them to one shot.”

In order to get stops, Joe Mazzulla says his team will need to close out better, get their hands up in Miami’s airspace, and not allow as many open threes in transition. Boston did a much better job of that in Game 1 when it held the Heat to just a 32.4 clip from deep.

“We can control our transition defense and we can control a decent percentage of those 3s,” Mazzulla said. “And so that’s the first step is always going back to taking away the things that you can control.”

Typically, the Celtics are in control of that area of the game. Not only do they have a top-tier 3-point defense, but they were also the third-leading team in shot contests this season.

Horford played a huge role in that area, claiming the fourth-best shot-contesting rate in the league.

“They are going to do what they are going to do, so we just have to be prepared to execute what we do and making sure that we’re engaged at a high level defensively, which I expect our group to be,” said the veteran big. “We’ve been very consistent with that all year, and we have to show it again.”

KP Looks to Bounce Back in Miami

Another rare occurrence in Game 2 was how limited Kristaps Porzingis was on the offensive end. Miami held him to just 1-of-9 shooting from the field, which represented his fewest field goals in a game all season in non-injury-shortened games.

However, Porzingis is not letting such a performance affect him mentally. He expects to bounce back in Game 3 and deliver something closer to the 7-of-13 effort he had in Game 1.

“Nothing changes for me; good game or bad game, I stay the same,” he said. “We looked at the things we can do better. I looked at my possessions. I’ll make sure I’m better offensively, 100 percent.”