Kevin Garnett has a reputation of getting into his opponents’ heads.

On Tuesday, the Celtics did the job without him.

In Game 2 of their playoff series with Miami at TD Garden, the Celtics beat the Heat, 106-77, to take a 2-0 series lead as Garnett served a suspension for his Game 1 altercation with Quentin Richardson. Their dominant basketball rattled Miami.

“They just had us talking to each other, blaming each other,” said Heat forward Michael Beasley. “We missed a couple shots, missed a couple rotations, and failed as far as mentally.”

The Celtics and Heat were tied after the first quarter. But Boston went on a 21-0 run in the second to break the game open. They led by as many as 33 in a game in which Glen Davis scored 23 points in place of Garnett and Ray Allen hit seven 3-pointers.

The Heat, on the other hand, shot just 38 percent. Dwyane Wade was held to under 30 points for the second consecutive game while no one on his team scored more than 13. (Jermaine O’Neal scored had just two points off of 1-for-10 shooting.)

“We’ve got to do a better job as a team against this team,” said Wade. “One player can’t win it. We need everyone to come in and be positive and have positive input. We’ve got a couple guys who are struggling right now. As always do as a team, we’re going to stick together. That’s the only reason we’re here now, the only reason we have success.”

There was more to this game, though, than the Heat being outscored. On the defensive end, the Celtics outrebounded them, 50-33, and had seven steals.

All of the missed baskets, missed rebounds, and overall missed opportunities piled up for Miami.

“Mental breakdown,” is how Beasley characterized the loss. “We let our missed shots and our missed rotations just take us out of the game mentally. We were almost fighting each other sometimes, and any time you get a team talking to each other like that and just out of it mentally, these type of games will happen.”

Even though not everyone on the Heat felt dissension on the court (“I don’t know if it was one another, I think we were just frustrated with the situation,” said Richardson), team leader Wade said the team must learn from any internal conflicts.

“There’s always going to be disagreements when things aren’t going right,” he said. “You can’t point too many fingers. You learn from it and you move on. In this league you can’t hold grudges because we all mess up. We all aren’t perfection. It’s just a time where frustration sets in. There is not going to be pats on the back when you’re losing by 30. Not at all.

“Guys are going to be willing to take criticism, that’s the only way you’re going to get better, if everyone’s willing to take criticism and understand their mistakes and try to move on and learn from it. Yeah, there were some things said to guys, but it’s been like that all year. We just bounce back from it. Normally you want to bounce back the next play and try to correct it, but in this case we have to bounce back the next game.”

The Heat are eager to face the Celtics on their homecourt, where they will have their own crowd behind them. (C’s fans let their feelings toward the Heat be known in Game 2 with a constant barrage of boos and jeers.) Even though they did not accomplish their original goal of winning one, if not both, games in Boston, they feel they can regroup in time for Game 3 in Miami.

“It was a very embarrassing game, and now the next step for us is that mental toughness, that mental stability,” said Miami coach Eric Spoelstra. “Where the mental toughness will come in is keeping this what it is. They did what they had to do. They won two games at home. This was one was an embarrassing loss.

“It is one loss, it is not four losses. And what we can control right now is getting our minds right and taking care of the most important game, Friday, Friday night. So that will be our test, in terms of being able to bounce back by keeping our mental stability, and that’s usually been a strength of ours all season.”

As Wade mentioned, it’s not unusual for teams to have frustrating nights. But the difference in the postseason is, there are only so many chances to correct those mental mistakes. The Heat are now two losses away from elimination and head to Miami looking to right their wrongs.

“You’ve got to be on guys. I’m going to be on guys,” said Wade. “As a leader myself, and Udonis (Haslem) as captains of this team, we’re going to take it upon ourselves to make sure that going forward it’s strictly business, that it‘s not about nothing else. That it’s all about win, win, win no matter what. So that’s where we’re at. We’re always going to be a team that’s going to be loose, we’re going to joke together and have fun, but it’s time to learn and time to learn from our mistakes.

“We have to do that and we have to come out and show it.”