From there, nearly everything went the Hawks' way.
"That's the best I've seen them play defensively," Hawks coach Mike Woodson said after his team allowed its fewest points in a game this season. "It was a total team effort across the board."
Maurice Evans scored 12 points and Al Horford finished with 10 rebounds for the Hawks, who scored the final 14 points of the third quarter, blowing open the game on the way to snapping a three-game losing streak.
Dwyane Wade had 21 points and eight rebounds for Miami, which lost for the first time in five games. The Heat missed nine straight shots during one second-half lull, plus were outscored 23-4 in fast-break points and were a mere 4-for-10 from the foul line, compared with Atlanta's 24-for-32.
"We came out like we were supposed to, with a lot of energy," Wade said. "But this is a good team. They didn't get rattled at all. They came back and made plays and got back in the game."
The Heat held Atlanta to 38 percent shooting. Problem was, Miami only connected on 39 percent of its shots.
"They shot a terrible percentage, too," said Heat forward Udonis Haslem. "We just didn't defend. We fouled and put them on the line. I think they shot about three times as many free throws as we did. That's where the game was won."
Wade came in averaging 34.7 points over his last six games but missed nine straight shots at one point.
"We just tried to make it tough on him," Johnson said. "We just tried to make those other guys beat us."
Miami was without rookie forward Michael Beasley, who sat out with the flu. It was the first game missed this season by Beasley, who is Miami's second-leading scorer behind Wade.
And yes, it's still relatively early, but both sides gave the game a certain significance.
The win -- just Atlanta's third in Miami since Nov. 1, 1996, a span of 24 games -- left the Hawks alone in second in the Southeast Division and fourth in the Eastern Conference, the spots the Heat would have occupied by winning.
"Big game tonight," Cook said to no one in particular as he walked through the locker room before tipoff.
Early on, the Heat looked ready, too.
Miami's game-opening run was its best start this season, by far. And after 7 minutes, the Heat were shooting a sizzling 8-for-12, running out to an 18-5 lead.
It didn't last.
Over the rest of the half, they were 9-for-32. That 13-point cushion was long gone by intermission, and once the Hawks started rolling, Miami couldn't offer any resistance.
"We understand that anything is possible when we have three more quarters," Smith said. "It was early on. We didn't give up on ourselves. We're a resilient team when it comes to fighting back."
Atlanta had 10 fast-break points in the third quarter alone -- compared with zero by Miami -- and outscored the Heat 14-0 over the final 3:59 of the period.
Johnson had 11 points in that quarter, only four fewer than the entire Heat roster, and the Hawks pushed the margin to 75-55 when Zaza Pachulia's baseline jumper dropped with 55 seconds left in the third.
Pachulia ended the quarter by trying a desperation, one-handed, 80-footer: It didn't miss by much.
"It became a real grind-out, toughness-type game," Heat coach Erik Spoelstra said. "They were able to respond and grind it out and turn an ugly game into a victory."
The Heat are hopeful Beasley will play Sunday at Memphis. ... Bibby shot a layup over the top of the backboard late in the first half, trying to drop a very-high archer over the outstretched arms of Wade and Udonis Haslem. ... Miami was 8-0 when leading after the first quarter. The Heat were up 25-20 after the first 12 minutes Friday. ... Heat vice president of player personnel Chet Kammerer will have the court at Westmont College in Santa Barbara, Calif. named for him Saturday. Kammerer coached there from 1975 through 1992.