Jaylen Brown took off the mask — revealing a guy who suddenly couldn’t miss.

Brown scored 31 points, most of them after removing a protective facial device he's worn for two months, and the Boston Celtics moved to the brink of advancing to the second round with a 129-121 victory over the Atlanta Hawks on Sunday night.

Jayson Tatum also had 31 points for the Celtics, who now lead 3-1 with the best-of-seven series shifting back to Boston for a possible clinching game Tuesday.

Brown stunned his teammates by removing the mask during a timeout early in the second quarter after making only 1 of 7 shots. Marcus Smart joked that no one recognized Brown at first; after all, he's been wearing the black shield since sustaining facial contusions in February.

“Maybe it was all my head," Brown said. "I just needed a different look.”

The Celtics sure liked his new look. Brown went 11 of 15 from the field the rest of the way.

“As soon as I took it off, things started to turn around a little bit,” he said.

Both of Boston's big stars came through when it mattered most.

Brown and Tatum combined to score their team's final 16 points, thwarting every attempt by the Hawks to even the series.

It was an especially satisfying victory for Brown — not only because he ditched the mask, but doing it in the metro area where he was born and raised.

“It's bittersweet, man, growing up here,” the 26-year-old Brown said. “My first game was a Hawks game. I was sitting in the nosebleeds. My aunt, who was in attendance tonight, bought me tickets to my first game for my seventh birthday.”

Boston never trailed after grabbing a 4-3 lead on Derrick White's basket just over a minute into the game.

Tatum delivered a huge 3-pointer off a loose ball with two minutes remaining, pushing the Celtics to a 118-106 lead.

After Trae Young swished a long 3 to provide Atlanta's last gasp, Brown knocked one down from beyond the arc seal it for the Celtics.

Smart added 19 points and White 18.

Young had another big game for Atlanta with 35 points and 15 assists, but it wasn't enough. De'Andre Hunter chipped in with 27 and DeJounte Murray had 23.

“They came out with a sense of urgency, and it showed,” Young said. “They're a really good team. They're here for a reason."

Hunter ripped off eight straight points, including a couple of 3s, and then delivered a thunderous dunk that brought the Hawks within 53-49.

But Boston closed the first half on a 12-4 spurt, capped by Smart's 3-pointer that sent the visitors to the locker room with a 65-53 lead and sapped a lot of energy from the home crowd.

Smart was in the Celtics lineup and looked just fine after a hard fall near the end of Game 3.

He landed on his tailbone while battling for a rebound, prompting Boston to list him as a game-time decision. But coach Joe Mazzulla declared his guard "good to go” well ahead of tipoff.

“The back locked up a few times, but I got through it OK,” Smart said.

BENCH HELP

After the Atlanta bench came up big in Game 3, the Celtics’ backups carried a major load Sunday.

Especially Robert Williams III, who had 13 points, a game-high 15 rebounds and blocked two shots.

“When he's healthy, he's probably the best defender in our league,” Brown said, "He has such a presence on the game."

Malcolm Brogdon contributed 14 points and four assists. In all, the Boston reserves outscored the Hawks’ bench 30-21.

KEEPING IT CLEAN

The first week of the playoffs has been marred by flagrant fouls, ejections and suspensions.

There have been no major issues in the Celtics-Hawks series, though Young did pick up a flagrant foul for grabbing Tatum's arm on a drive through the lane in the third quarter.

“I think it's been a clean series,” Hawks coach Quin Snyder said. “Physicality isn't necessarily wrong. It's part of the game. You can be physical. I think the word is ‘aggressiveness’ as much as anything. Both teams have done that.”

TIP-INS

Celtics: After getting outrebounded 48-29 in Game 3, Boston came out much more determined on the boards. They held a 19-9 edge at the end of the first quarterback, 32-20 at halftime and finished with a 49-42 edge. ... C Al Horford didn’t score any points but handled the dirty work. He had 11 rebounds, five assists and two steals. Horford attempted just two shots, both from 3-point range.

Hawks: F John Collins made only 1 of 9 shots and finished with 5 points. … Hall of Famer Dominique Wilkins missed his second straight game as commentator on the Hawks regional telecast because of an illness. He is expected to return for Game 5.