LeBron James was loudly booed and jeered throughout his first game back in Cleveland since signing with the Heat, but responded with a season-high 38 points.
James scored 24 points in the third quarter.
"I have the utmost respect for this franchise, the utmost respect for these fans," James said afterward.
Dwyane Wade scored 22 points and Chris Bosh chipped in 15.
"This is the first time I have seen this connection all year long," said coach Erik Spoelstra.
James stopped short of apologizing for leaving the Cavaliers, but acknowledged the way he was treated as a young professional.
"So many things went through my mind," James said. "I have nothing bad to say about these fans at all. We grew from the year before I got here, a 17-win season to the last two years I was here, we had the best team in the league in the regular season. I understand their frustration. I was frustrated also because we didn't accomplish what we wanted to. I wish this organization and these fans, who are great, the best."