The Yellow Jackets (2-0) weren't very good from distance in making just 3-of-20 3-point shots, and for a long time they weren't very good in the paint, either, before whipping the Blue Hose (0-2) badly in the paint in the second half.
The bigger team from the Atlantic Coast Conference had a 22-4 edge in points in the paint after trailing 25-24 at intermission.
Presbyterian senior guard Khalid Mutakabbir led the Blue Hose with 13 points, 12 of them coming in the first half.
The Yellow Jackets started the second half with an 18-2 to take a 42-27 lead on freshman Chris Bolden's dunk with 11:45 remaining in the game.
Georgia Tech's second-half success came in stark contrast to the Jackets' first half problems. They moved easily to a 12-2 lead, but then struggled with the Presbyterian zone for the remainder of the first half.
The Yellow Jackets missed their next 11 shots -- 10 of them jumpers and seven of them from 3-point distance -- and the Blue Hose used an 18-4 run to take a 20-16 lead on Mutakabbir's second straight 3-pointer with 3:53 left. All of Tech's points in that span came on senior point guard Mfon Udofia's free throws.
Presbyterian outscored Georgia Tech 10-6 in the paint in the first half.
The Yellow Jackets matched that paint total on its first three possessions of the second half as forward Carter Jr., center Daniel Miller and then Carter again scored from point-blank range for a 30-27 lead that Georgia Tech never lost.
After Georgia Tech pushed its lead to 15 points with the 18-2 run, Presbyterian never drew closer than 46-38. That came when William Truss scored a layup for the Blue Hose with 2:45 to go.
Despite their size advantage, the Yellow Jackets carved out a modest 34-30 rebounding edge, but Presbyterian suffered 18 turnovers to Georgia Tech's seven, and the Yellow Jackets made 11 free throws to Presbyterian's three.
Mississippi State freshman guard Malik Newman will withdraw from the NBA draft, but sources told ESPN he might explore other opportunities besides returning to Mississippi State.
Seton Hall sophomore Isaiah Whitehead will stay in the NBA draft and not return for his junior season.
Washington State's trio of Josh Hawkinson, Conor Clifford and Ike Iroegbu have withdrawn from the NBA draft and will play their senior season with the Cougars.