Free throws by Embiid and Tyrese Maxey, who scored 16 points off the bench, pushed the advantage to 98-93.
“That stung for us as a whole team,” Harris said of blowing big leads in two losses.
The 76ers opened the second half with a flurry of four threes, including three by Curry, for a 12-0 run to open the second half that gave Philadelphia a 59-51 lead.
Embiid fell on top of Collins on the court, and Collins then shoved the 76ers center before both rose to their feet.
Collins’ jumper to open the game helped Atlanta score 10 of the game’s first 12 points.
Hawks guard Bogdan Bogdanovic left in the fourth quarter with right knee soreness and was ruled out for the remainder of the game.
After making only 12 of 39 free throws in the first five games of the series, Simmons made two of four attempts, all in the final period.
Richard Bland, a European Tour journeyman, 48, who was ranked 1,010th in the world in 2019, is tied with Russell Henley after two rounds of the U.S.