Trae Young made three three-pointers and dealt out 13 assists as the Hawks rallied from a 10-point deficit with five minutes left to send the series back to Atlanta.
As TD Garden rose to its feet, Robert Williams III stood in the corner. Al Horford’s corner three-pointer in the fourth quarter tied the game for the Hawks, who had trailed by 10 minutes prior.
The Hawks’ fourth-quarter comeback also crept up on them. It fell from the rim and landed in Williams III’s palms, and he scored to take the lead.
Williams III traveled to the opposite basket and ascended to the rim as Trae Young slid by Horford, the Hawks guard draining three long-range shots and dishing out a flurry of assists to give Atlanta the lead with 5:14 remaining after trailing by 10 points.
After winning the jump ball at midcourt, Williams III raced to the basket and completed an alley-oop. This and two free throws by White with 7.3 seconds remaining gave Boston the opportunity to secure the series.
Young snatched it away. With one-second remaining and one more shot from deep range, the Hawks saved their season, 119-117.
Brown donned his right-hand protection after abandoning it for an 11-for-15 performance in the fourth game. During the first half, he shot 10 of 13 from the field, made two three-pointers, and scored 23 points, extending the team’s momentum.
His satchel expanded to provide Tatum with a bounce pass in the pocket for a layup that should have been open. He jumped into the post and hit Jalen Johnson with a succession of spinning post moves before finishing inside, and he subsequently made a left-handed layup.
The run gave the Celtics a 59-48 lead after they had trailed for the majority of the first half, despite the Hawks making 60% of their three-point attempts, including baskets from John Collins, Jalen Johnson, and Onyeka Okongwu, players who averaged below 30% from deep during the regular season.
Joe Mazzulla tested the durability of the run by matching Collins’ minutes with Robert Williams III in drop coverage, which resulted in a 1-for-3 span from the Hawks’ big man.
Meanwhile, Malcolm Brogdon entered midway through the quarter to build and manage Boston’s lead, connecting on a pull-up two, a three, and a three-point play through De’Andre Hunter to swiftly reach double figures in scoring.
Tatum scored after a delayed start when Horford, who had blocked five shots in less than three quarters, stopped Young in the lane, sent Brown out, and Brogdon found Tatum cutting across the paint with a pass.
Young finished the quarter with a long two-pointer that bounced and landed, keeping the Hawks within 10 points going into halftime.
Throughout the game, Atlanta double-teamed Tatum, who started 5-for-15 from the field, but he frequently found Smart to his side flaring or rolling out of screens.
Smart shot 4-for-8 from the field, and Brown found him in the same position in the middle of the third quarter when Sam Hauser entered the game after a strong first-half performance garnered him double-digit minutes.
After a Tatum lives ball turnover and a three-pointer, Young’s alley-oop to Collins kept the Hawks within single digits.
He met Hauser at the rim, who he had isolated throughout the series, in assist position after Young drove Rob and Hauser rejected him and sent Tatum out in transition for a crucial dunk.
Hauser made two of four three-point attempts and recovered a loose ball that Tatum mishandled, threw it up from the free throw line, and it fell after striking the rim twice and the backboard.
He received an errant Tatum pass in the corner that was deflected by two Hawks and returned it to Tatum for a wide-open layup.
Young led the early offense and bombarded Hunter, Collins, and Okongwu with passes in the fourth quarter as Boston prepared for a 9-for-16 Hawks charge.
Blake Griffin entered the game and roused the audience by deflecting off Atlanta the second of two missed free throws by Brown to set up a Tatum mid-range shot.
As they raced up the court, White blocked Young for a second time, prompting Young to wave off official Josh Tiven. Several plays later, Tatum connected with Brown in the corner for three before finding White downhill for two.
Mazzulla called a timeout to end a stretch of three consecutive baskets by the Hawks, which had given the Celtics an eight-point lead. Tatum lost the ball to Hunter, who deflected Tatum’s pass with White wide open in the lane and pursued it into the backcourt.
Young made a pair of step-back three-pointers as Horford returned to switching against him, halting the next attempt before fouling him on the subsequent drive. Three Young free throws put the Hawks ahead by one point after a costly technical penalty by Tatum.
Williams III made a crucial stop and threw down an alley-oop before Smart played tenacious defense and fouled Young at midcourt, giving the guard 35 points and 13 assists to go along with his one-point lead.
Brown assisted White in driving downhill, and arguably the series MVPs combined to extend Boston’s lead at the free-throw line. Young regained the advantage within seconds, advancing to his fifth and final three.
With 0.5 seconds remaining, Tatum, who shot 8-for-22, launched a supplication that landed far to the right of the rim.