Turner put in the go-ahead basket with 1:30 remaining, David West drained a clutch 3-pointer and Indiana survived Chris Bosh's attempt at the buzzer to hold off the Miami Heat, 84-83, in a highly anticipated duel between the Eastern Conference powers.
The buildup to this showdown lasted three months after defeating one another on their home floors in December.
The Pacers, who clinched the Central Division with the win, entered with a two-game lead for the East's top seed -- a crucial advantage having lost Game 7 of the conference finals in Miami last year.
Paul George led the way with 23 points and eight rebounds, Roy Hibbert scored 21 and Stephenson and West netted 15 and 13, respectively, for Indiana, which had dropped three of four coming in.
LeBron James filled the box score with 38 points, eight rebounds and five assists but committed six of Miami's 19 turnovers as the Heat fell to 4-5 over their last nine games.