Goran Dragic had 15 points and Hassan Whiteside added 14 to lead the Heat, who had a two-game winning streak snapped.
Coming off a game in which they tied for their season low with 73 points in a 24-point loss to the Orlando Magic on Tuesday, the Knicks had 63 points at the half and piled it on in the second half, scoring 59 more points in their highest-scoring contest since late-February.
New York claimed an early lead, going into the second quarter up 34-23, and led at the half by 13.
Dotson, who entered Friday averaging 3.0 points per game, made 12 of 21 shots, including 4 of 10 3-pointers. The Knicks turned to the rookie guard early when Michael Beasley exited the game in the first minute with a knee contusion.
New York later lost Tim Hardaway Jr., who injured his left ankle late in the game, and Emmanuel Mudiay (headache).
Luke Kornet added 17 points off the bench for the Knicks, who shot 50.6 percent from the field and 48.6 percent from 3-point range. Kyle O'Quinn had 14 points and 14 rebounds and Courtney Lee added 10 points off the bench for New York, whose reserves outscored the Heat bench, 68-46.
James Johnson had 12 points for Miami, which shot 39.8 percent from the field and 25.9 percent from deep. Kelly Olynyk had 11 points and Wayne Ellington added 10 off the bench for the Heat.
The win was not without its costs for the Knicks, and not only in terms of injury. New York's win dropped it a half-game behind Chicago, which lost on Friday to the Boston Celtics, for eighth place in the lottery race.
The Knicks stay at home for a quick turnaround on Saturday, when they host the Bucks.
Miami (43-37) hosts the Oklahoma City Thunder on Monday.
--Field Level Media
Miami | New York | |
Goran Dragic 15 | Scoring | Damyean Dotson 30 |
James Johnson 4 | Assists | Frank Ntilikina 9 |
Hassan Whiteside 6 | Rebounds | Kyle O'Quinn 14 |
Kelly Olynyk 6 | Free Throws Made | Trey Burke 4 |
Wayne Ellington 2 | Steals | Tim Hardaway Jr. 2 |
James Johnson 2 | Blocks | Kyle O'Quinn 3 |
Team | Points | FG% | 3PM-3PA | FTM-FTA | Assists | Rebounds | Blocks | Steals | Turnovers |
Miami | 98 | 39.8 | 7-27 | 21-22 | 20 | 42 | 5 | 7 | 13 |
New York | 122 | 50.6 | 18-37 | 14-21 | 33 | 51 | 5 | 7 | 12 |