Al Horford’s putback layup with 1.9 seconds left earned the Hawks victory and the top seeds will try to put a seal on the series in Washington on Friday night.
Horford led Atlanta with 23 points and 11 rebounds and his 10-for-18 shooting stood out in a game that was full of errors and bad misses.
The Hawks shot only 41 per cent from the floor, but that was four per cent better than the Wizards, with both sides struggling badly from three-point range.
Scores were tied going into the final 30 seconds with DeMarre Carroll putting the Hawks 80-78 in front, only for Paul Pierce to drain a three and give the Wizards a lead.
But Atlanta would make the most of the last possession as Dennis Schroeder’s lay-up bounced off the back-board and Horford timed his jump to perfection to secure the loose ball and put up the winning shot.
“A heck of a play by Al,” Atlanta coach Mike Budenholzer said. “He went and got it, found a way to put it back in.”
In the Western Conference, the top seeded Golden State Warriors also claimed a 3-2 series lead when they ran away from the Memphis Grizzlies 98-78 at the Oracle Arena.
NBA MVP Stephen Curry drained six of the Warriors’ 14 three-pointers, following up his outstanding game four performance with another stellar display that included 18 points along with seven rebounds and five assists.
Klay Thompson scored 21 points for the Warriors, who will try to wrap up the series on Friday in Memphis.
“This is big,” said Curry, whose team bounced back from a two-game losing streak in Memphis on Tuesday. “We wanted to capitalise on the momentum we got in game four.”