Jaylen Brown described the Boston Celtics as "embarrassing" after they were blown out by the Miami Heat in Game 3 of the Eastern Conference Finals.

Celtics coach Joe Mazzulla, who has faced criticism throughout the series, blamed himself for the 128-102 loss, as Boston fell to the eighth-seeded Heat for a third straight game.

No team in NBA history has recovered to win a seven-game playoff series when trailing 3-0 and Miami has its first chance to wrap up the series at home on Tuesday.

In a road game the Celtics felt they had to win after two shock home losses, Miami's lead grew to as much as 33 points in the third quarter.

Jayson Tatum led Boston with just 14 points while finishing 6 of 18 from the field and Brown was held to 12 points on 6-of-17 shooting. The two All-Stars were a combined 1 of 14 from 3-point range.

"I don't even know where to start," said Brown after the game, per ESPN. "It's an obvious letdown. I feel like we let our fan base, organization down. 

"We let ourselves down. And it was collective. We can point fingers, but in reality, it was just embarrassing.

"To their credit, they’re playing well above their means.They’re ballin’ right now and I’ve got to give them respect.

"Gabe Vincent, Martin, Strus, Duncan Robinson, guys that we should be able to keep under control are playing their [butt] off.

"The series isn't over yet. It's looking bad, but you come out, have some pride about yourself."

The Celtics were favourites to win the NBA Championship before the series began but now look like a team in crisis just seven days on from their big Game 7 win over the Philadelphia 76ers in round two.

"I just didn’t have them ready to play," said Mazzulla, who is in his first season as head coach.

"Whatever it was, whether it was the starting lineup or an adjustment, I have to get them in a better place, ready to play. That’s on me.

"I think some of the defensive identity has been lost and we have to get that back."

While a comeback to reach the Finals from here would be miraculous, Tatum insists Boston has to first and foremost recover some pride.

He said: "It was tough. From the beginning of the game, we were turning the ball over. We didn't shoot the ball well, they shot extremely well and it felt like we never recovered.

"As tough as tonight was, we just got to try to move on. Prepare, get ready, practice, film and stuff for tomorrow.

"Obviously we're in a tough position but we've got to have some pride, bounce back and just be better come Tuesday."

Jimmy Butler has proven inspirational for the Heat in the postseason far but in Game 3 Miami showcased its roster depth.

Gabe Vincent scored a career-high 29 points and Duncan Robinson added 22 off the bench, propelling the Heat to a lopsided victory that puts coach Erik Spoelstra on the brink of a sixth NBA Finals appearance with the team.

The Western Conference finals also look like they are set to reach an earlier than expected conclusion, with the Denver Nuggets enjoying a 3-0 lead over the Los Angeles Lakers ahead of Game 4 on Monday.