Miami (5-1) broke out to a 46-14 edge in the first quarter before pushing their advantage to 59-18 in the third quarter Sunday at American Airlines Arena in Miami. Houston (3-3) never held a lead. The Heat matched their best start in franchise history with five wins in their first six games.
"I wish I could bottle it up," Heat coach Erik Spoelstra said of the team's energy. "The guys have really been working up to try to get to our identity, which is bringing a great deal of energy and commitment to the defensive end.
"This is obviously one of the most-challenging teams to defend in the league."
Heat star Jimmy Butler scored 13 points and had five assists in the first quarter, helping the Heat to a franchise-record advantage. The Heat's 22-point lead was also the third-biggest edge in the NBA's shot-clock era. Meyers Leonard helped the Heat to the early jump with 11 points in the opening frame.
The Rockets outscored the Heat 32-25 in the second quarter, but still trailed 71-46 at halftime. Leonard led the Heat with 10 points in the third quarter, pushing the lead to 99-71. James Johnson scored 10 points for the Heat in the fourth frame, with Miami outscoring Houston 30-29 in the final 12 minutes.
"They came out and blitzed us," Harden said. "They brought an energy and effort from the beginning of the game that we could match. The score showed it. The second, third and fourth quarter, we were pretty much even. They are a team that plays extremely hard on both ends of the floor."
The Heat had 38 assists and 15 turnovers in the win, compared to the Rockets' 19 assists and 22 turnovers. Miami shot 43.9 percent from 3-point range. Butler had 18 points, nine assists and seven rebounds for the Heat.