The Heat established franchise-record lows in points scored and field goal percentage (25). Miami finished off a brutal game by scoring just nine points in the fourth period after managing only 10 in the second.
Toronto broke a five-game losing streak against a team that has won but 12 times all year. Miami was coming off a victory over Milwaukee Tuesday and was trying to win back-to-back games for the first time since early December.
Rasho Nesterovic added 12 points for Toronto, which shot 53 percent from the field and cruised to a 58-28 advantage at halftime.
Chris Quinn scored 14 for Miami, which attempted 23 three-point shots and made only five of them.