When the Milwaukee Bucks clamped down on Harris, Horford backed down defender Larry Sanders, who leads the league in blocked shots per game, and hit a baby hook shot with 5.9 seconds left as the Hawks rallied late for a 103-102 victory on Saturday night.
"I was trying to get Devin a handoff," Horford said. "They played that real good. So I just kind of went ahead and ... I just made a strong play to the basket."
Horford's shot came after a driving layup by Monta Ellis had given the Bucks a 102-101 lead with 10.8 seconds left. Ellis missed a running shot in the lane as time expired.
Horford finished with 23 points and 11 rebounds, Jeff Teague also scored 23 and added nine assists, and Harris contributed 21 points for Atlanta.
"I knew when we got the ball into Al's hands, he was going to make a play and he did what a great player is supposed to do. He finished it off," Teague said.
The tight game featured 18 lead changes and was tied 13 times, but the Bucks led by as much as 10 late in the fourth quarter before the Hawks rallied.
"We were able to maintain our composure, particularly in the second half," Atlanta coach Larry Drew said. "When we went down ten, we didn't panic. We came up with some big plays down the stretch."
Drew praised the play of Horford.
"I thought Al Horford was huge. He came up with some big baskets. Defensively, he also altered some shots."
Ersan Ilyasova had 19 points and newly-acquired J.J. Redick added 16 points and seven assists for Milwaukee. Sanders added 12 points and 19 rebounds, one off of his career high.
After taking a 100-93 lead, the Bucks went more than 3 minutes without a basket.
A 3-pointer by Josh Smith cut Milwaukee's lead to 100-99 and after a shot-clock violation by the Bucks, Horford dunked to put the Hawks up 101-100 with 1:28 remaining.
Ilyasova then had a layup attempt blocked and Kyle Korver missed from 3-point range for the Hawks. After a Bucks turnover, Horford missed a hook shot with 15.2 seconds left.
"I thought our guys played hard. I thought we played well enough to win the game," Bucks coach Jim Boylan said. "Every time we seemed to get some sort of comfortable lead against them, they'd bang a 3.
"The games keep coming, so you don't have a chance to really feel sorry for yourself."
Milwaukee jumped out to a 27-19 lead at the end of a first quarter that featured three technical fouls. The Bucks' Brandon Jennings was whistled for arguing a foul call and officials assessed a double technical on Milwaukee's Samuel Dalembert and Atlanta's Zaza Pachulia after they tangled under the basket.
Pachulia, who set a Hawks franchise record with seven offensive rebounds in the second quarter, also picked up a flagrant foul in the fourth when he fouled John Henson on a drive to the basket. He and Dalembert pointed at each other and exchanged words.
"I told him that I set the franchise record with seven offensive rebounds in a quarter. He was mad," Pachulia said.
Redick made his first appearance in a Bucks uniform midway through the first quarter. Acquired from Orlando in a Feb. 21 trade deadline deal, Redick entered to a standing ovation.
"I feel like I was brought here to help this team win and secure a good playoff position," he said. "I'm a competitor and I certainly didn't want to start off with a loss. We did some good things tonight and I enjoyed playing with this group."
Milwaukee worked to acquire Smith, Atlanta's leading scorer, right up until the deadline, but he ended up remaining with the Hawks. "Josh has been a super player for us," Drew said. "I'm glad he's still a Hawk." ... Although both teams play in the Eastern Conference, Milwaukee and Atlanta met for the first time this season. "We're almost into March and this is our first meeting. It feels a little weird," Drew said. ... Atlanta's DeShawn Stevenson wasn't available Saturday night due to a coach's decision not to play him in the second of back-to-back games in order to minimize wear on his knees. ... University of Wisconsin men's basketball coach Bo Ryan was in attendance. Harris played for Ryan at Wisconsin.