BOSTON -- Coach Brad Stevens knew hours before the Boston Celtics' game vs. the Atlanta Hawks on Friday night there was something different about Amir Johnson.

"You could see it in our shoot-around -- he was going a hundred miles an hour in our 4:15 shoot-around, so you could tell he was locked in and engaged," Stevens said, after Johnson scored 19 points, grabbed eight rebounds and added four assists, three steals and three blocked shots.

It was the forward's best game as a Celtic, as he led Boston to a 106-93 victory over the Hawks.

"He was great the whole night on both ends," Stevens said.

Johnson, who signed a two-year free-agent contract with the Celtics, was coming off a three-game stretch that saw him score just 16 points and grab 15 rebounds in over 55 minutes. He took only 12 shots in the three games and was averaging 7.7 points and 5.7 rebounds in his first seven games in his new uniform.

Friday night, he scored Boston's first five points and had seven in the first quarter. His assault on the boards helped the Celtics (4-4) pile up a 50-35 rebounding advantage, 17-5 on the offensive boards. That is how you take 103 shots (hitting 42, 11 of them 3-pointers) in a game.

"I try to find a way every game to bring some energy," Johnson said.

Forward Kelly Olynyk hit two 3-pointers during a 21-9 run over the final 5:10 of the third quarter and guard Isaiah Thomas drained back-to-back 3-pointers to stave off an Atlanta charge in the fourth as the Celtics evened their record at 4-4.

The Hawks (8-3) were playing without their coach, Mike Budenholzer, because of a family emergency. Assistant coach Kenny Atkinson took over and while the players were clearly trying to win for their coach, there was something missing from one of the Eastern Conference's best teams.

The Celtics built a 15-point lead two minutes into the fourth quarter before the Hawks, led by backup guard Dennis Schroder and little-used center Mike Muscala, ran off 12 straight points. They got no closer -- but did cut a seven-point lead down to three with 3:03 remaining.

Boston then reeled off 10 points in 1:33, the last five by forward Jae Crowder, to ice the game. The Hawks were shut out for the final 3:03.

"I thought Mike was really good," said Atkinson. "He gave us some size in there, he gave us some physicality. He was part of the group that made a comeback."

Thomas led the Celtics with a game-high 23 points, 10 assists and five rebounds.

Asked about Johnson, Thomas said, "He brought energy from the jump. We need that from him ... that's what he does -- he brings energy, he gets rebounds, he rolls to the basket, he does a lot for us offensively and defensively, and we just need him to stay at that level."

Olynyk came off the bench with 15 points and Crowder added 13 points and eight rebounds, while forward Jared Sullinger had 10 points and 10 rebounds, his second straight double-double.

Atlanta's big three, forward Paul Millsap, center Al Horford and guard Jeff Teague, who came into the game averaging a combined 51.8 points,19.9 rebounds and 14.2 assists, weren't factors. They finished with 33 points, 10 rebounds and 13 assists.

Millsap led the Hawks with 14 points and eight rebounds, while Horford posted 13 points, six rebounds and eight assists. Teague's second-half time was limited after he twisted his left ankle near the end of the first half. He played in the second half, but said his ankle was "very sore" after the game.

The game was tied at the half. Eight points by guard Kyle Korver in a 1:33 span helped the Hawks take a 60-59 lead with 5:23 left in the third quarter. The Celtics then took over while the Hawks continued a sloppy evening that ended with 17 turnovers.

"Give them credit. I thought their physicality gave us some issues, their offensive rebounding was big for them," said Atkinson.

NOTES: Atlanta assistant coach Kenny Atkinson said his goal Friday was to keep the players on schedule with head coach Mike Budenholzer away from the team for a family emergency. "I just wanted to keep us on a routine, our normal routine, from shoot-around to what we do pregame -- just keep our guys on a normal routine," Atkinson said before the game, adding there was no update on Budenholzer. "But this group's been together for a while now. It's a pretty close-knit group, they're obviously close with Bud, so it will be interesting to see how they react tonight with all the emotions and everything that's gone on." ... Celtics G Avery Bradley missed his second straight game with a calf bruise. ... A moment of silence was held before the game because of the tragedy in Paris.