Mario Chalmers added 11 points and nine assists for Miami, which turned 27 New York turnovers into a franchise playoff-record 38 points.
J.R. Smith scored 17 for the Knicks, who have lost 11 straight playoff games dating to 2001. Carmelo Anthony missed 12 of 15 shots and finished with 11 points and 10 rebounds, and Baron Davis added 10 points for New York.
The Knicks lost starting guard Iman Shumpert to a knee injury in the third quarter.
Game 2 is Monday in Miami.
BULLS 103, 76ERS 91
In Chicago, Bulls star Derrick Rose will miss the rest of the season because of a torn anterior cruciate ligament in his left knee.
Rose was helped off the court late in Chicago’s playoff-opening victory over the Philadelphia, a staggering blow for a team eyeing a championship run.
He scored 23 points and was playing more like the league’s reigning MVP after missing 27 games because of injuries during the regular season, but his season came to an end as the Bulls were wrapping up an impressive win.
Rose crumbled to the ground after he drove the lane with about 1:20 left and the Bulls leading by 12. He was going for a layup when he came to a jump-stop and seemed to change his mind as the 76ers’ Spencer Hawes and Lavoy Allen rotated over, passing off to a teammate before an awkward landing.
Elton Brand led Philadelphia with 19 points.
MAGIC 81, PACERS 77
In Indianapolis, Jason Richardson and Jameer Nelson scored 17 points apiece to help sixth-seeded Orlando, playing without Dwight Howard, surprised third-seeded Indiana in Game 1.
Howard, the Magic’s leading scorer and the league’s top rebounder, will miss the rest of the season after having back surgery.
The Magic played defense Howard would have been proud of down the stretch, overcoming a seven-point deficit by holding the Pacers scoreless for the final 4:05.
David West scored 19 points, Danny Granger added 17 and Roy Hibbert had eight points, 13 rebounds and nine blocks for the Pacers.
Granger traveled with 7.5 seconds left and the Pacers trailing by three.