The Pacers trailed by three with 2.03 minutes remaining when Turner came off the bench to make two consecutive layups, giving Indiana a one-point lead and sealed their first win in the past three games.
Miami’s Chris Bosh missed a jumper with two seconds left on the shot clock that could have given the reigning champions a one-point victory, instead the Pacers claimed their second victory over Miami in the past three meetings this season.
Indiana hold a three-game advantage in the race for the Eastern Conference’s top seed, ahead of Miami (48-22).
Paul George, who had a tremendous two-hands dunk on LeBron James in the fourth quarter, led the Pacers with 23 points, and Roy Hibbert contributed 21.
Lance Stephenson added 15 points for Indiana, before being ejected midway through the fourth quarter after picking up his second technical foul.
James led all scorers with 38 points for Miami who led by as many as ten points in the third quarter.
Miami will host Indiana on 4 April for the final regular-season between two potential finalist in the Eastern Conference.