Smith hauled down 15 rebounds and Johnson dished off six assists as the Hawks stayed hot with a third consecutive win and their sixth victory in seven games.
Atlanta again played without injured forward Al Horford, who will miss 3-4 months after sustaining a shoulder injury last week.
Leandro Barbosa scored 22 to lead the Raptors, who played their third straight game without leading scorer. Andrea Bargnani has been sidelined by a strained left calf muscle.
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