The Heat closed the game on a 14-2 run.
James, who sat out Wednesday's loss to the Boston Celtics due to back spasms, finished 7-of-14 from the field. Ray Allen netted 18 points off the bench, while Dwyane Wade netted eight of his 14 in the final frame for Miami, which has won three of its last four but are still just 4-6 over its last 10.
Zach Randolph tallied 25 points and 14 rebounds to lead the Grizzlies, who had won six of their last seven contests coming in.
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