Pachulia, who had 13 points and 18 rebounds, scored after Joe Johnson missed a layup.
Jameer Nelson, who had five points in overtime, missed a last-second jumper for the Magic.
Johnson had 40 points and 11 assists for Atlanta, his third game with 40 or more points this season.
Al Harrington, who missed a shot at the end of regulation, had 24 points for Atlanta.
Nelson led Orlando, which had eight players score in double figures, with 18 points. Hedo Turkoglu added 16 but was called for a key offensive foul with 12.8 seconds left in overtime, setting up the Hawks’ game-winning play.
Nelson scored with 2:54 left in the extra session to tie it at 100, and his 3-pointer with 1:24 to play gave Orlando a 105-100 lead. Josh Smith and Johnson answered with 3-pointers for the Hawks.
The Hawks couldn’t hold a 96-92 lead with 1:16 left in regulation.
Nelson’s jumper cut the deficit to two and Turkoglu’s jumper tied it at 96— the eighth tie of the period and 22nd of the game.
Following Turkoglu’s basket, the Hawks called a timeout with 18.7 seconds left. Johnson worked the clock before passing to Harrington, whose last-second shot bounced off the rim.
The Hawks, who trailed most of the first half, leaned heavily on Johnson and Harrington to pull even at 58 at halftime.
Johnson, who had 21 points at the break, hit a 3-pointer with 2:41 left. Harrington, who had 14 points in the second period and 18 in the first half, hit two 3-pointers late in the half.
Howard finished with 13 points and 15 rebounds. Battie added 14 points.
The Hawks are 5-2 in overtime games. … Battie topped his season scoring average with eight points in the first 4:30 of the game. … Hawks G Salim Stoudamire was taken to the trainer’s room late in the third quarter with a sprained right elbow. He did not return to the game.