Tied 99-99 with 1.01 seconds to play, Hawks forward Pero Antic lobbed an inbounds pass to Horford, who was posted up on the opposite side of the lane. He caught the pass over Wizards forward Trevor Booker and quickly released the five-foot baseline jumper for the winner.
"It was supposed to be a lob for a dunk, but Booker did a good job, kind of pushing me away," Horford said. "As soon as I caught it, I just shot it. Since we've worked on it before, I was comfortable taking that shot."
"I thought I could get the ball," said Booker, who led the Wizards with 24 points and 14 rebounds. "But it went over my head. I didn't really get a chance to contest it. It hurts, considering what we've been through, losing by one point last game, and then in the game, fight back lost it that way. It hurts."
The Hawks took a 10-point lead into the fourth quarter but saw the Wizards cut the lead to 82-81 on a razzle-dazzle layup from Wall, who went behind his back for only his third field goal of the night with three minutes to play. He later hit a pull-up jumper with time running down on the shot clock to give the Wizards their first lead of the second half.
It wasn't pretty for much of the game, with both teams shooting poorly and turning the ball over often.
Wall hit just one of his first 10 shots from the field and found himself on the bench after jacking up an air-ball 3-point attempt in the third quarter. Wall's potential winning jumper at the end of regulation also failed to hit the rim. Wall finished with 13 points on 6-of-22 shooting from the field.
"I just don't think we were ready to play," Washington coach Randy Wittman said. "For 42 minutes, we didn't do anything. We would have been better off staying home and practicing. We take shortcuts, and you're never going to be a good team or a good player when you take shortcuts."
Both teams were coming off poor offensive performances and weren't crisp early. Airballs, missed layups and lazy turnovers marred a sloppy first quarter.
The Hawks (12-11), who shot a season-low 35.6 percent from the field in a Tuesday loss to the Oklahoma City Thunder, missed six of their first seven shots. The Wizards (9-12), who scored a season-low 74 points in a Monday loss to the Denver Nuggets, opened Friday's game 5 of 17 from the floor.
The quality of play picked up in the second quarter. The Wizards got a spark from their bench, with guard Glen Rice Jr. connecting on two 3-pointers, and center Jan Vesely adding a couple of baskets on the inside. The Hawks got going behind Horford, who hit 5 of 7 shots from the field in the first half, helping the Hawks take a 48-46 lead into halftime.
NOTES: Wizards G Bradley Beal returned to practice in limited capacity this week, but the second-year player does not have a timetable for his return from a stress injury to his right fibula. Beal, who was leading the Wizards in scoring, missed the last eight games. ... ATLANTA F/C Gustavo Ayon missed his second straight game with a left ankle sprain. ... The Wizards' bench, which entered the game averaging an NBA-low 13.4 bench points, scored 16 in the first half. ... Washington F Al Harrington underwent surgery on his right knee Monday and will be re-evaluated in four weeks. ... The Hawks head to New York City for a Saturday night game against the struggling Knicks before returning home to face the Los Angeles Lakers. ... The Wizards host the Los Angeles Clippers on Saturday night.