In the closing seconds, without a timeout, Atlanta missed two 3-pointers but grabbed two offensive rebounds before fumbling the ball away, which led to Mitchell's free throws.
Atlanta (10-19), which started the day a half-game out of the final playoff spot, trailed by 18 early in the second half when Clark hit a 3-pointer before outscoring the Fever (14-16) 41-32. The Dream got within two before Indiana's five-point possession blunted the rally.
Aliyah Boston had 14 points and 11 rebounds for Indiana and Damiris Dantas scored 33 off the bench. Clark had four 3-pointers, tying the rookie record of 85 by Atlanta's Rhyn Howard in 2022.
Tina Charles scored 21 to lead Atlanta, which moved the game to the home of the Atlanta Hawks and set an attendance record of 17,608, surpassing the crowd that attended the last game against the Fever (17,575). Howard had 16 points, Allisha Gray 12 — none after receiving a flagrant foul from Boston midway through the third quarter — and Jordin Canada 10 for the Dream.
Howard's 3 pulled Atlanta to 76-74 with 4:13 to play but after an offensive rebound Clark found Lexie Hull for an and-1 layup a minute later. Hull rebounded her missed free throw and fed Mitchell for an and-1 layup she converted for an 81-74 lead.
Nia Coffey made a 3 for Atlanta with just under a minute to play to make it 82-79.
Mitchell had 15 points and Boston 12, on a combined 12-of-21 shooting as the Fever took a 52-38 lead.
At halftime the gold medal team from the 1996 Atlanta Olympics was honored.
