The sluggish Celtics were beaten on the boards and turned the ball over 17 times in losing their second straight on the heels of nine victories in 10 outings.
Toronto never trailed, building a 12-point lead after one period en route to its fourth home victory of the season. Only New Jersey, Charlotte and New Orleans have fewer wins at home.
Kevin Garnett paced Boston with 17 points and eight rebounds.
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UPI Sports Results for September 19, 2014