The Hornets were trailing by 10 going into the final period, but Mason hit three 3-pointers while New Orleans was outscoring the Rockets 29-10 during the closing 12 minutes.
A 3-pointer by Mason gave the Hornets the lead at 73-71 with 6:31 to play and came during a 13-0 run.
It was the third straight win for the Hornets, who have captured five out of eight after losing 11 straight. The Rockets had won five in a row.
Greivis Vasquez and Jason Smith also had 17 each for the Hornets, who held the normally high-scoring Rockets to 40 percent shooting. Houston went 9-of-27 from 3-point range.
James Harden led Houston with 25 points, but no other member of the Rockets reached double figures.