James, who just celebrated birthday No. 23 - to match his uniform number - began the new year with another dominating performance, but one that began very quietly.
He took only five shots and scored four points in the first half. But after dropping in 13 points in the third, James scored 19 in the fourth, including 19 of Cleveland's 22 over the last 6:51.
James also got the assist on a 17-foot jumper with 2:33 left by Hughes, who came in shooting just 27 percent in his past five games. Hughes' jumper usually draws groans from Cavs fans, who have been tough on him all season. But this one, which put the Cavaliers ahead 85-82, was a welcome sight.
Hughes' shooting has been so off that one Cavs supporter even started a Web site: HeyLarryHughesPleaseStopTakingSoManyBadShots.com in protest. Hughes, though, quieted his critics for the night by going 6-for-10.
James did most of his damage from the outside in the final minutes, but he also made six straight free throws in the final 16.1 seconds as the Cavaliers held off the much-improved Hawks.
Hughes finished with 14 points and Drew Gooden 13 for Cleveland.
Joe Johnson scored 24 points and Josh Smith 20 for Atlanta, which could do little to stop James when it mattered most.