After surrendering a combined 61 points over the second and third quarters, the Heat stormed back in the fourth with a 34-point period, and then outscored the Hawks by two points in overtime thanks to two clutch free-throws from Michael Beasley with a shade over nine seconds remaining that gave Miami the lead for good.
LeBron James was simply sensational in the win, totaling a game-high 38 points on 16-of-28 shooting along with eight rebounds and six assists.
Without Dwyane Wade, Erik Spoelstra plugged in Ray Allen at starting shooting guard, and the 38-year-old delivered to the tune of 19 points on 7-of-10 shooting, and drained three free-throws when the Heat were down three with just seconds left in regulation.
Beasley and Chris Andersen scored 10 and 12 points, respectively, off the pine. The Heat finished with six players in double-figures.
For Atlanta, it was all about three-point shooting. As a team, the Hawks shot 50 percent (17-of-34) from beyond the arc, and received a career-high seven triples from Paul Millsap, who racked up 25 points and 10 boards in a losing effort.
Kyle Korver dropped in five threes of his own (15 points), while Al Horford recorded a double-double with 21 points and 11 rebounds.
Jeff Teague scored 26 points and dished out eight assists in a fine performance.