The Miami Heat are desperate to silence their doubters and are using outside criticism as fuel in their first-round playoff series against the Boston Heat, having levelled it up at 1-1.

That is according to forward Bam Adebayo, who had 21 points and was nine of 13 shooting in the Heat's 111-101 win at TD Garden on Wednesday.

Miami buried their hosts under a mountain of 3-pointers in Game 2, setting a franchise record for a postseason game by shooting 23 of 43 (53.5 per cent) from the field.

Speaking after the game, Adebayo said the way in which the Eastern Conference's eighth seeds have been written off by neutrals was spurring them on.

"We've been doubted a lot through our playoff runs, people saying we couldn't do a lot of stuff that we eventually did," Adebayo said.

"So for me and my team, why lose belief now? Our backs are against the wall. Everybody's against us. So just use that as fuel.

"Our guys believe we can win. So, let's make it mano a mano… a cage fight. Let's hoop!"

Caleb Martin joined Adebayo on 21 points with five 3s, being booed by the Boston crowd every time he touched the ball following his heavy collision with Jayson Tatum in Game 1.

Jaime Jaquez Jr. contributed 14 points with three 3s, Nikola Jovic added a trio of 3s and Haywood Highsmith came off the bench to sink three 3s.

Martin said Miami's new shoot-on-sight mentality was part of a plan drawn up by Erik Spoelstra, saying: "I think it was about realising that being passive hurts us. 

"We'd just be playing into their gameplan. We're too good of a shooting team to hesitate from 3."

Spoelstra himself said the Heat had taken the decision to be more proactive after being sunk by Boston's 3-point shooting in Game 1.

"I understand the math of it," the Miami coach said. "We're not going to shoot 50 of them. That's not realistic."