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Boston Celtics head coach Joe Mazzulla is a man of few words. During his interview with Allie LaForce of TNT in between the third and fourth quarters of Game 5 of the Eastern Conference finals on Thursday night, he uttered just 10 of them. The first seven stood out.

"It just starts with our defensive identity," Mazzulla said, when asked why the Celtics were the best version of themselves in a wire-to-wire, 110-97 victory over the Miami Heat, which kept their season alive and forced a Game 6 back in Miami on Saturday. 

If you just scanned the box score, it may not seem like this was a defensive masterpiece by the Celtics, but the Heat's 51.3% shooting from the field and 39.1% mark from 3-point land don't tell the full story. Yes, they may have hit shots, but they never got into a comfortable rhythm because of the Celtics' pressure right from the opening tip.

The Heat won that jump ball and tried to set up Bam Adebayo with a post iso on the right side of the floor. Only, Al Horford forced Adebayo to catch the ball all the way at the 3-point line, which meant the Heat big man had to put the ball on the deck in the middle of the floor to get to the basket. That was a bad idea with Marcus Smart lurking; the Celtics guard reached in for a steal, dove to secure the loose ball and found Jayson Tatum for a fastbreak layup. 

"Physicality on the defensive end from the start," Grant Williams said. "Smart set the tone the first play of the game, which set our defense up for the rest of the game and we gotta just continue that pressure."

The Celtics were totally locked in. 

Their pick-up points were in the backcourt or right at halfcourt. They were making the Heat work just to get into their sets, which they then had to start further away from the basket. Here's a sample of four possessions from the first quarter. 

The Celtics were picking up the Heat early and making them work 

They built on their initial pressure by flying around off the ball and being smart with when and where they helped. Here's a play late in the first half where Jaylen Brown jumps the passing lane for a steal and gets an easy fastbreak layup. That all happens because Smart is up on Caleb Martin early, which makes the initial pass out to the wing longer and more predictable, giving Brown the ability to time the steal. 

In the third quarter, the Heat tried to post up Adebayo with Smart guarding him, so Horford shades down toward the paint and makes a hard double team. As Adebayo kicks out to Jimmy Butler, Derrick White has already slid over to the elbow to congest the lane Butler wants to drive into and gets the steal. 

On the occasions when the Heat were able to get into the lane, the Celtics' discipline and rim protection made things difficult. While the Heat did shoot the ball well overall, that was primarily on tough jumpers; at the rim they were just 17 of 26, a 65.4% mark that was below league average, and in the paint overall they were 26 of 47. 

Just a few possessions in, White plays tremendous defense and goes vertical to force a Butler miss.

A few minutes later, Tatum does the same.

In the second half, White refused to bite on a Butler pump fake, then Tatum stands tall to contest a wild running layup from Max Strus.

"Yeah, D-White, second team all-defense this year for a reason," Tatum said. "He's a big part of our team, our identity, things we try and do on the defensive end. He's a very smart basketball player on both ends, and his awareness, his instincts, they showed tonight."

The Celtics do not have the same level of defense as they did last season, but they still finished second in the league in defensive rating and can dial it up when necessary. That's just what they did in Game 5 with a brilliant display that perfectly blended energy and organization. The result was 27 points off of 16 turnovers, which included 13 steals. 

And it's that type of intensity that they'll need more of in Game 6 if they want to become just the fourth team in NBA history to force a Game 7 after going down 3-0. 

"We played with great intensity on defense, and I think we just set the tone from the jump," Brown said. "We've got to be able to do that and carry that over into the next game. We have got to expect their best punch next game."