"He was all over the place," Beasley said of Horford. "He's one guy who does all the little things. Everything was working for him.
Horford, a second-year player out of Florida, recorded his 10th double-double of the season. His previous high of 20 rebounds was Feb. 26, 2008, against the Los Angeles Lakers.
"I just realized I had to be a little more aggressive on offense," said Horford, who shot 8-of-14. "I've kind of been coasting throughout the year."
His numbers don't indicate that. Horford is averaging 10.9 points and 8.8 rebounds a game.
The Hawks (33-25) expanded their lead to 2 1/2 games over the Heat (30-27) for fourth place in the Eastern Conference.
"They [Miami] know what's at stake. They're trying to get that fourth spot and we're trying to hang on to it," Atlanta coach Mike Woodson said.
"Coach told us it was a playoff-type game. Miami's just right behind us, so we needed to make a statement. That's the way we have to play from now on," Horford said.
Added Wade: "We'll play them again and it will be the kind of game that goes back and forth. They feel they can beat us and we feel we can beat them. It's one of those teams we feel is a possible first-round matchup in the playoffs, so every game is going to go down like this and be very competitive."
Atlanta took its biggest lead at 60-46 with 2:09 left in the third period on a pair of free throws by Johnson and led 64-53 entering the fourth quarter.
Beasley got the Heat within 84-80 with a basket with 1:16 left, but Miami never got closer as Johnson added four straight free throws to stretch the lead with 41 seconds left.
The Hawks led 36-32 at intermission as both teams shot poorly from the field. Horford had 13 points and 10 rebounds for Atlanta, but the Hawks shot 14-for-39 (36 percent) while the Heat were 15-for-43 (33 percent).
The Hawks' biggest lead of the half was 28-17 before going on a 5 1/2-minute drought while the Heat went on a 12-0 run for their only lead of the half. A basket by Jermaine O'Neal with 4:15 remaining made it 29-28.
Miami went without a point for five minutes in the opening quarter, but Atlanta couldn't take advantage, leading only 14-10 when Beasley broke the streak with a basket with 3:06 left.
Wade, the NBA's leading scorer, had only six points at the half on 3-of-8 shooting. Johnson, Atlanta's top scorer, had only five on 2-of-7 shooting.
The Hawks hosted Miami for the first time this season in the third of four games between the teams. They split the first two games in Miami. ... Wade had three steals, giving him 667 for his career, a team record. "I'm excited to know my name will be in the record book for something other than scoring. I'm very honored to be No. 1 in anything," he said. ... Atlanta G Mike Bibby (flulike symptoms) and Smith (family matter) missed the Hawks' last game, a 110-109 loss at Denver. Bibby said he has hardly eaten in the last three days because of the illness. He started, but played only 19 minutes and was 0-for-7 from the field.