The Celtics defeated the other team 118-84, with 25 points apiece from Derrick White and Jaylen Brown.
Despite the absence of center Kristaps Porzingis due to injury, they were dominant the entire time.
“I believe I’ve played them in the playoffs four times, but it doesn’t matter,” said Jayson Tatum of the Celtics, who finished with 16 points and 12 rebounds.
“We fulfilled our duties. We attended to business.”
The Orlando Magic or the Cleveland Cavaliers will be the next opponents the Celtics face.
The sixth game of the best-of-seven series is scheduled for Orlando on Saturday, and the Cavaliers are ahead 3-2.
Bam Adebayo scored 23 points for the injured Heat team.
