Georgia (12-10, 3-6 Southeastern Conference) won for the first time since an 82-69 victory over Arkansas on Jan. 19. The Gamecocks (12-11, 3-6) trailed 46-29 at the half and never challenged.
Georgia built a double-digit lead before it was 5 minutes old and stretched the margin as high as 21 points. The Gamecocks never got closer than 14 in the second half.
With the Bulldogs down to just seven scholarship players, Gaines has taken the team on his back. The senior guard scored a career-best 32 points in a loss at Florida over the weekend, then equaled the second-best showing of his college career against the Gamecocks.
Gaines scored 19 points in the first half, hitting 4 of 5 from beyond the 3-point stripe.
The Bulldogs, one of the worst-shooting teams in the SEC, made 16 of 28 (57 percent) in the opening half. Georgia outrebounded the Gamecocks 20-14, was 8-for-9 at the foul line and was 6-for-9 from 3-point range.
South Carolina seemed content to only launch 3s, making only 4 of 18 in the first half. The Gamecocks shot only 36 percent before halftime.
The teams split their season series. South Carolina defeated the Bulldogs 62-56 on Jan. 30, the second of Georgia's five consecutive losses.
Gaines had plenty of help. Jeremy Price had 19 points and 12 rebounds, while Dave Bliss also contributed a double-double with 12 points and 10 rebounds. Terrance Woodbury chipped in 13 points.
Devan Downey led the Gamecocks with 20 points, while Zam Fredrick added 15. Former Josey star Dominique Archie only had nine points.