What happened in between the other 80 games defined a major difference between the two teams.
Thaddeus Young had 20 points and nine rebounds in Philadelphia's 100-87 triumph over the Heat in the regular season finale Wednesday night.
The Sixers (19-63), who began the campaign with a 114-110 win at home over the Heat on Oct. 30, suffered through a NBA record-tying 26-game losing streak this season.
The two-time defending NBA champions finished second in the East behind Indiana, and will take on the Charlotte Bobcats in the first round of the playoffs. The Heat have won 16 in a row during the regular season versus the Bobcats and will face them for the first time in the playoffs.
Michael Carter-Williams, a top candidate to win Rookie of the Year, totaled 12 points and six rebounds for the Sixers.
The Heat used a 22-7 spurt to take a 27-19 lead in the first quarter, but then trailed 29-27 after 12 minutes. Casper Ware's 3-pointer capped the 10-0 spurt to end the period.
Philadelphia went 10-of-14 from the field in the second to gain a 55-51 halftime edge.
Young's layup finished an 11-2 burst for a 69-59 lead at the midway point of the third, and the Sixers expanded the lead to 84-66 moving to the fourth. Miami was just 5-of-16 from the floor in the third.
The Heat got as close as seven in the fourth when Ray Allen's 3-pointer made it 89-82 with 7:08 remaining, but the Sixers scored the next six points.