Hill finished 5 of 11 from the field and 12 of 16 from the line for the Bulldogs (17-12, 9-7 Big South Conference). He led five players in double figures including Harold McBride with 16 points, Adonis Burbage and Jarvis Davis with 11 points apiece and Tyrell Nelson with 10.
Gardner-Webb jumped to an 18-8 start and led 35-24 at the break.
Burbage sank a 3-pointer to start the second half and Liberty answered with a 16-6 run to close within four points, 44-40, with 14:18 to play. Hill scored seven straight points - including a pair of layups and a tip shot - to give the Bulldogs their biggest lead 73-57 with 48 seconds left.
Theo Johnson led the Flames (7-22, 1-15) with 15 points.