"The guys now can't go back on this," Heat coach Erik Spoelstra said. "They've showed me defensively what they're capable of."
Dwyane Wade led all scorers with 26 points, including 12 in the third quarter as the Heat took command of the game.
LeBron James had 15 points and seven assists and Chris Bosh had a double-double with 11 points and 10 rebounds. Forward Udonis Haslem had a double-double coming off the bench with 11 points and 11 rebounds.
"When me and Chris (Bosh) decided to join him (Wade), and even the rest of the guys, this is what we envisioned," said James.
"Is it going to be a 26-point win every night? No, it's the NBA and we know that, but the fans, they came out and the least we could do is play hard for them."
Dwight Howard scored 19 first half points for Orlando but fouled out midway through the fourth quarter without scoring in the second half to lead the Magic. The Magic starters combined for a meager 37 points, and just seven in the second half.
"I think their defense was very good," Magic coach Stan Van Gundy said.
"I think that their length and the way that they got into the passing lanes made it tough for us to get good ball movement. Passing's a major problem with our team. It really is."