Jimmy Butler said the Miami Heat's ability to call each other out for "BS" helps them turn games around like they did against the Boston Celtics.

Miami recovered from a 17-point deficit to beat the Celtics 106-101 and take a 2-0 lead in the Eastern Conference Finals on Thursday.

Butler, who had 14 points in Game 2, said the Heat spoke to each other openly when things were going wrong.

"We look each other in the eye and tell each other when it's BS," he told reporters.

"Spo [Erik Spoelstra, coach] is going to do it, I'm going to do it, Jae [Crowder] is going to do it, Tyler [Herro] is going to do it, Duncan [Robinson], all the way down the line, because it's unacceptable.

"We know when we're not playing the way that we're supposed to be playing. And as bad as it sounds, it's like a switch. It just turns on, and, 'oh, there we go right there.' I'm telling you, straight face communication, move on and get it done."

The fifth seeds in the Eastern Conference, Miami hold a surprise 2-0 lead over the Celtics after being led by Bam Adebayo, who had a double-double of 21 points and 10 rebounds.

But Butler warned his team they had achieved nothing heading into Game 3 on Saturday.

"We haven't done anything. We haven't. We can't get excited that we're up 2-0 because as good as it is to be 2-0, it could easily be 4-2 Boston," he said.

"So we're going to come into the same way knowing that we've got to be better and stay humble about it. Not getting too high.

"Stay in the middle, keep playing basketball the way we're supposed to be playing."