That was evident during the TNT telecast of Tuesday night’s season-opening loss in Miami.
He was wearing a microphone and barking out calls on the floor and words of encouragement to Rajon Rondo  when things weren’t always going well.
On Thursday, before the Celtics home opener tonight against the Bucks, he was barking out something else.
“The defense has got to come a lot faster, and that’s something that’s come a lot faster in the past than the offense,” Pierce said of Boston’s 120 points allowed in a 120-107 loss to the Heat. “I’m pretty surprised we scored 107 points, to tell you the truth. Usually, the defense, we pick it up pretty fast. We understand our schemes, our rotations. But I just think we have to understand the type of atmosphere it was going to be. Some of the guys have never been in that atmosphere before, first game, playing against the defending champs on the road. We have to pick up our intensity, understand the moment, understand where we’re at and understand the type of game it’s going to be and raise our game.”
Doc Rivers  thought his coaching staff had too much time to prepare and filled their players’ minds with too much information.
“I think our on-ball defense was average because our help defense was worse,” Rivers said. “If everybody is up guarding their own man and there’s no help and guys see gaps [in the defense], they’re taking it. What really upset us, every key guy got every shot he wanted, where they wanted the whole, and that’s a bad defensive night.
“It was team wide. It was spread. Like I told them, from the coaching standpoint, I thought we had way too much time to prepare for it and we put way too much stuff in their head. I thought they were thinking more than playing on instinct. I told our coaches we share in that. We had them doing a couple of different things and that’s not who we are defensively.”
Pierce said it’s nice of Rivers and the staff to shoulder some blame but the players need to be better.
“A lot of the coaches, they’re going to take a lot of the blame but as individuals, we have to take the blame because we were out there also,” Pierce said. “It’s a combination of the two. We’re all in this together. They’re not going to be able to take the whole [share] of the blame. There’s no way we should give up a 120 points no matter what defensive scheme we run. We might as well sit on the sideline and watch them run up and down the court than give up 120 points.”
“Just a lack of communication,” added Rondo, when asked what the biggest defensive issue was Tuesday. “It is what it is. We’re professionals. They may have given us a lot but at the same time, we should be able to handle it. It was only Game 1, we had a week to prepare for them. It wasn’t like we [only had] two days to prepare. We had a week to prepare for them. We just didn’t execute anything.”
Rivers also had another piece of advice for fans who like to read box scores. Tuesday’s box score had the Celtics beating the Heat, 27-12, in fast break points.
“It helps to get back,” Rivers said. “The most misleading stat – and that’s why you should all tear up – whenever you look at the stat sheet and it says transition [fast break] points, you should always just tear that up because it’s not true. They had far more transition points in the game than us in the game.
“We didn’t get back. We didn’t ever set our defense. They saw in in the film [Thursday]. I would love to say it was Miami’s great speed – and they have all that – but you don’t get back on defense, you can’t play defense. To me, that was the No. 1 thing.”
So what did the Celtics work on Thursday?
“Pick and roll coverage, getting back and working on a little bit of transition defense to start practice,” Rondo said. “We lost the game. Whether it was by 20 or 10, we lost the game. We gave up a lot of points but it’s Game 1.
“It wasn’t just those guys, it was everyone. It was myself, Kevin [Kevin Garnett ]. For a stretch in the third quarter I was thinking too much. It’s not just the new guys, it was the core as well. So, we just have to find a way and we will. We’ll get better, starting [tonight].”