Gay provided 20 points and Lucas got 10 of his 19 in the fourth quarter as the Raptors went on a 16-5 run to break open a close game.
Kyle Lowry (14 points, 10 assists) and Jonas Valanciunas (11, 10 rebounds) also supplied some crucial help as Toronto notched a second straight win.
The Hornets, meanwhile, lost for the first time in three games despite 19 points from Robin Lopez and 17 from Greivis Vasquez.
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