Gaines opened the overtime period with a 3-pointer and Charles Mann scored the next four points for the Bulldogs (9-7, 3-1 Southeastern Conference). Mann scored six of his nine points in the extra period.
It was the third straight overtime game for Arkansas (12-5, 1/3 SEC). The Razorbacks previously lost to No. 7 Florida but beat No. 13 Kentucky in overtime.
Even with the extra period, Georgia held Arkansas 23 points below its SEC-leading average of 84.7 points per game.
Arkansas has lost five straight SEC road games.
Georgia took a 56-34 advantage in rebounds. The Bulldogs improved to 8-0 when holding opponents under 70 points.
Georgia struggled with poor shooting in the first half but had to be encouraged by the low-scoring pace as Arkansas led 29-28 at halftime. Mann, named SEC player of the week on Monday, leads Georgia with his average of 13.6 points per game but was scoreless in the half while missing each of his five shots from the field.
Arkansas frustrated Georgia with its oppressive man-to-man defense, often forcing bad shots when the Bulldogs couldn't get off a pass. The Bulldogs had nine turnovers in the first half and shot only 29 percent (9 of 31) from the field but stayed close by taking a 27-15 advantage in rebounds and 15-6 edge in points off rebounds.
Mann made one of two free throws to open the second half but went to the bench with three fouls early in the half. Mann's replacement, freshman J.J. Frazier (5-10, 150), struggled in his matchup against Gulley, who hit two 3-pointers and scored on a drive in a span of eight straight points for Arkansas that gave the Razorbacks a 41-34 lead.
Georgia answered with a 6-0 run and finally took a 49-48 lead on a Brandon Morris layup with 3:16 remaining.
After Frazier made one of two free throws, Alandise Harris drove past Thornton for a layup for Arkansas, tying the game at 50-all. Georgia pulled ahead with two free throws by Brandon Morris before Madden answered with two free throws for Arkansas.
The teams traded turnovers before a missed 3-pointer by Frazier gave Arkansas the ball. Coach Mike Anderson called timeout with 21.8 seconds remaining. Madden missed a 3-pointer and the Razorbacks couldn't get off another shot before the end of regulation.