LeBron James finished with 23 points and 11 rebounds in 30 minutes of play. Dwyane Wade finished with 22 points on 9 of 14 from the field.
Shannon Brown led the Suns with 18 points in 21 minutes off the bench. Luis Scola had 15 points and eight boards.
New Miami guard Ray Allen became the 24th player in NBA history and fourth active player to reach 23,000 points.
The Heat dominated from the opening tip, beginning the game on a 10-2 run. They led 30-16 after the game's first 10 minutes.
Phoenix never led, and the game was never particularly close after the first quarter. At one point in the fourth, Miami led by 30 points.