LeBron James produced another dominant display to record 32 points and 10 rebounds as the defending champions moved to within one victory of a fourth successive trip to the NBA finals.
Miami made a fast start to the game as Chris Bosh, who finished the night with 25 points, scored the first eight points of the game to give the home supporters an early sign of what was to come.
After taking a 27-19 lead in the opening quarter, Miami's charge was briefly halted as the Pacers reduced the deficit to five at the interval.
However, Miami were in full control once again in the third quarter as they continued to pull away from the visitors, who struggled without much contribution from either Lance Stephenson or Roy Hibbert.
Indiana hit back to move within nine points of the Heat with 90 seconds remaining, but a three-point play from James moments later ensured there would be no dramatic finish.
Miami can book their spot in the finals by securing the Eastern Conference title in Indiana on Wednesday night.