BOSTON >> Isaiah Thomas had 21 points to help the Boston Celtics rally from 26 points down to beat the Miami Heat 98-88 on Wednesday night.
Coupled with Atlanta's loss to Washington, Boston earned the fifth seed in the Eastern Conference. The Hawks' loss also gave Miami the third seed and its fifth Southeast Division title in six years.
The Celtics will face the fourth-seeded Hawks in the first round. Miami will take on No. 6 seed Charlotte.
Avery Bradley added 17 points and seven rebounds. Evan Turner finished with 16 points for Boston.
Joe Johnson and Hassan Whiteside each had 19 points to lead the Heat. Goran Dragic added 18 points and Dwyane Wade finished with 17.
Boston swept a regular-season series from Miami for the first time since 2009-10.
Miami jumped out to its double-digit lead before the Celtics roared back in the third quarter using a 23-3 run to get back into the game.
The Heat looked to be running away in the first half.
That changed in the third quarter with the Heat scoring just five points — all by Johnson — on 5-for-20 shooting as the Celtics closed to within 67-63 entering the fourth.
The period also ended with a shouting match between Marcus Smart and Dragic. Udonis Haslem, who was out resting a sore left foot, also got involved coming off the bench. Double technical fouls were issued to both sides.
It didn't slow down the Celtics, who kept attacking and eventually took the lead on three-point play by Kelly Olynyk in the opening minutes of the final period.
The Celtics tied their season low for points in quarter with 13 in the first quarter Wednesday. Miami ended the quarter on a 23-4 run.
Dragic nearly outscored Boston by himself with 12 points.
Heat: Five points in third quarter was a season-low for points in a quarter. ... Miami swingman Justise Winslow, who was questionable with a sprained left ankle, was able to play.
Celtics: Outscored the Heat 18-0 in the paint in the third quarter.
Celtics: Will face Atlanta in the first round.
Heat: Will face Charlotte in the first round.