Mills finished with 32 points and Tim Duncan provided 16 with 13 rebounds for the Spurs, who broke open a close game with a 12-4 run in the fourth quarter.
Nando De Colo put in 15 points as San Antonio rang up a fourth win in five games.
The Bobcats were paced by Al Jefferson with 26 points and nine rebounds.
Gerald Henderson added 23 points.
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