LeBron James scored 22 points, Dwyane Wade had 18 and eight assists and the Heat used a complete team effort to overwhelm Indiana and grab a 2-1 best-of-seven series lead.
It was the first home defeat of the playoffs for the Pacers, who will try to rebound in Game Four on Tuesday back in Indiana.
After losing on a buzzer-beater in the opener, and controlling most of their Game Two triumph, the Pacers were knocked on their heels in the rematch.
Miami surged in the second quarter where hot shooting helped them seize a 70-56 lead by halftime.
While James had performed well all series, some of his struggling team mates came to life in a game that saw the Heat make 54 percent of their field goals.
Udonis Haslem missed just one shot in scoring 17 points, while Chris Bosh had two three-pointers and added 15.
The Pacers were not quite as efficient. David West had 21 points and 10 rebounds and Roy Hibbert recorded 20 points and 17.
Paul George, who has emerged into the spotlight for his strong play on both ends, missed seven of his 10 shots and settled for 13 and eight assists.
Last season, Miami were challenged en route to their championship by the Pacers during a tough second round series that saw the Heat trail 2-1.
But this time, the champs grabbed the pivotal Game Three and put the pressure back on Indiana.