“Everything is connected”

Game 1’s tend to be feel out games and even though the Celtics have faced the Heat in two out of the last three Eastern Conference Finals, these versions of the teams are different from years past.

The major players are the same. Jayson Tatum and Jaylen Brown are still Boston's headliners. Jimmy Butler and Marcus Smart are still members of each other's Mutual Admiration Club. Al Horford, Bam Adebayo, and Robert Williams are still wildcards in the frontcourt. Head coach Erik Spoelstra is still one of the greatest tacticians and motivators on an NBA sideline.

However, there is a new face on the Boston bench. Despite some familiarity with Spoelstra and the Heat dating back to the bubble, this is Joe Mazzulla's first time in the driver's seat after Brad Stevens and Ime Udoka were at the helm in Orlando and last year's title run respectively.

And after a Game 1 loss that included a 46-25 third quarter run, the Celtics coach had plenty to answer for after his team not only relinquished homecourt advantage, but seemed shellshocked after two consecutive series where they seemingly fumbled games away, particularly at TD Garden.

"There were moments where we played well. There were moments where we executed and there were moments when we didn’t," Mazzulla said after a long film session and light practice on Thursday. "This series is a test of discipline, is a test of mentality, and we’ve got to be extremely detailed in our effort and our consistency."

Mazzulla emphasized his team’s attention to detail and its spacing, not so much the lineup on the floor. Pressed on personnel decisions like inserting Payton Pritchard into the rotation and not going back to Grant Williams, Mazzulla was cagey about the move.

“We’ve developed an identity this year to play a bunch of different ways. We just can’t look at it as ‘it’s this way vs. that way.’ We have a lot of depth. We have a lot of diversity, versatility. We have to be able to use that and flex in to that.”

We can all second guess Mazzulla’s decisions. It’s easy to think that the path that the Celtics didn’t pick would have lead to a win and the easiest straw man is someone who didn't play. We'll never know what the butterfly effect would have been had Williams saw the floor, but it's clear that Mazzulla had his reasons.

"I like his shooting. I like his aggressiveness," Mazzulla said of using Pritchard as a third guard off the bench. "I like his ability to change the momentum and the energy when he’s in the game. I think he brings a level of physicality in our pick-and-roll defense which is important in this series."

Tactically, there are areas that they can address, too. Defensively, they went big and tasked Al Horford and Jayson Tatum with defending Butler rather than going with Marcus Smart and/or Jaylen Brown. Transition defense and finding shooters in the half court were areas of concern.

And after scoring 40 points in the paint in the first half, Boston shot more threes in the second half with a more familiar shot profile that they’re accustomed to.

"They switched defenses and switched more in the second half and switching defenses slows you down," Mazzulla said of the adjustments between the first and second half on Wednesday.

But the head coach knows it's more about intentionality and execution.

"You’ve got to fight for your spacing. You’ve got to fight for advantages. You’ve got to fight to create separation. Being able to make the adjustment on how we play versus one defense versus a switching defense is important and we just have to fight for that. We can generate those threes by creating that separation, by creating advantages."

Ultimately, if Game 1 was a reconnaissance mission, the most important intelligence Boston gathered was possibly on themselves. Miami-Boston III is mental warfare, but you have to wonder how much of the battle is inside their heads. Horford recognized it when practice got a little loosey goosey before the opener and they ceded some ground. Derrick White saw it on the floor on Wednesday.

"Everything is connected. You let someone see the ball go in a couple of times on easy ones — their confidence is high,” White said.

The players and coaches have acknowledged that they only seem to respond when they’ve got their backs against the proverbial wall and tonight's game will serve as a gut check more than anything else.

The popular narrative is that the Celtics are simply more talented. They’re younger and more athletic and if they just gave more effort, they’d win against the underdog Heat. The sounds bites fit the frame of that story so far and some of that may even be true. A higher level of concentration could have swayed a handful of possessions and maybe even the outcome of Game 1.

However, that’s a dangerous mentality to have because for all the bravado about Heat culture and Jimmy Butler, Boston just has to be better, period. Mindset goes a long way for sure, but in the end, just win the game.