Gallinari made four 3-pointers in the game and three of them came during the closing 12 minutes. The Nuggets trailed by three to begin the fourth quarter, but came back to defeat Houston for the sixth time in as many meetings.
Denver, which began the fourth period on a 13-0 run, has won five in a row overall and has 12 victories in January.
Houston, which had a three-game winning streak snapped, was led by Jeremy Lin with 22 points.
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