Erik Spoelstra has no doubt the Miami Heat can inflict the sort of brutal defeat that the Boston Celtics doled out in Game 4 as the Eastern Conference Finals heads towards its climax.

A 102-82 loss in Boston on Monday night came on the back of Miami scoring a trifling 11 points in the first quarter, with Jimmy Butler scoring just six points all night and no Heat starter reaching double figures.

The visitors shot just 33.3 per cent from the field (30 of 90), with Boston's win squaring the series at 2-2 and setting up Game 5 in Miami on Wednesday evening as a pivotal occasion.

Coach Spoelstra said: "More than anything, our offense really hurt us at the beginning. They weren't getting the sort of purposeful execution that you need to on the road. [Boston] were able to get some relief points from that and get to the free-throw line. They did a better job of getting into us and rotating guys into the paint."

It was 57-33 by the halfway mark, and Spoelstra admitted the Heat simply failed to ignite. Yet he says Miami can swiftly set the game aside and dominate the next time the teams meet on court, saying it would not surprise him if the tables are turned.

"We've got guys that love these kinds of moments, the playoffs. You've just got to stay together," Spoelstra said.

"This is part of the playoffs. There are these extreme highs and lows, a lot of emotion. You just have to stay the course, stay together. What you're looking at is a great series. It's 2-2. You have to embrace that. Hopefully this competition beings out the absolute best in all of us.

"They got the best of us tonight. We'll take this hit and then get to Miami and get ready for Game 5. Whatever they have done to us, we can do to them."

Jayson Tatum led Boston with 31 points. The Celtics led by 32 points at one stage before Miami began to claw back the deficit late on.

"We're not making any excuses. They outplayed us tonight, for sure," said Spoelstra.