After building a reputation as the competition's surprise package in the first half of the season, the Heat have struggled massively since the start of February, winning just three of their last 10 games.
Seth Curry went eight-for-nine from behind the arc for the Mavericks in the eight-point loss.
The Milwaukee Bucks continued to look like strong favourites for the title during a 47-point demolition of the Oklahoma City Thunder.
The visitors looked powerless against an offensive onslaught from Milwaukee, who were without starting guard Khris Middleton in the 133-86 blowout.
Giannis Antetokounmpo finished with 32 points for the Bucks in just 27 minutes on the floor.
Each of Charlotte's starting five contributed on both ends of the floor to help hand the Raptors their first back-to-back defeats of the year.
The Memphis Grizzlies' hold on eighth spot in the Western Conference is in jeopardy following a 104-101 loss to the Sacramento Kings.
De'Aaron Fox top-scored for the Kings with 25 as Memphis fell to their fifth straight loss.
Utah's Donovan Mitchell went four-for-six from deep to help propel the Jazz to a 10-point win.
Brandon Ingram scored 29 points to lead the New Orleans Pelicans to a 116-104 win over the ClevelDe'Aaron Foxand Cavaliers, the Detroit Pistons struggled to a 113-111 win against the Phoenix Suns and the Los Angeles Clippers had little trouble against the Denver Nuggets in a dominant 132-103 victory.