Marcus Smart, Tyler Herro both sit as Celtics crush Heat in Game 4

Marcus Smart, sidelined by a sprained right ankle, celebrates as the Celtics dominate Game 4 of the Eastern Conference finals.

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Both Eastern Conference finalists were without key starters in Monday’s Game 4, but the Boston Celtics handled their absence far better than the Miami Heat.

Even with reigning Kia Defensive Player of the Year Marcus Smart sidelined by the sprained right ankle he suffered in Game 3, Boston clamped down on Miami for a stifling 102-82 victory that evened the series, 2-2.

Playing without Kia Sixth Man of the Year Tyler Herro (groin), the Heat shot just 33.3% from the floor as they were held to their second-lowest point total of the playoffs and third lowest of the entire season.

The outcome was never in doubt as the Celtics led by 18 points after the first quarter and 24 at halftime. They were fortified by the return of starting center Robert Williams III (knee), who totaled two of Boston’s 11 blocked shots in 18 minutes.

Game Recap: Celtics 102, Heat 82 (Series tied, 2-2)

Celtics All-Star Jayson Tatum shook off a minor neck injury to score 24 of his game-high 31 points in the first half. Heat All-Star Jimmy Butler, who missed the second half of Game 3 with knee inflammation, was held to six points on 3-for-14 shooting.

Miami’s starting lineup scored just 18 points, with P.J. Tucker and Max Strus both going scoreless in 36 combined minutes.

Game 5 is Wednesday in Miami (8:30 ET, ESPN).

“Just got to muster that same energy when we came off a win as well as a loss,” Celtics coach Ime Udoka said. “This is a three-game series now. Can’t always just flip the mindset when we come off a loss and get a little desperate.”