Donta Hall added 13 points and seven rebounds, and Daniel Giddons scored 11 points for the Crimson Tide (10-6, 2-2 SEC). Alabama snapped a two-game slide behind 35 points from the bench.
Wesley Myers scored 15 points to lead the Gamecocks (10-6, 1-3 SEC), who have lost three of four.
Alabama trailed only once, at 2-0, but didn't pull away from the Gamecocks until midway through the second half. Avery Johnson Jr. and Petty hit 3-pointers on consecutive possessions to ignite the Crimson Tide's closing push. Johnson finished with 10 points.
Alabama outscored South Carolina 15-1 during a four-minute stretch that saw the Crimson Tide's lead balloon to 69-46 with seven minutes left.
The Crimson Tide got off to a hot start. Petty hit a pair of 3-pointers to fuel an early 14-0 run that gave Alabama a 23-8 lead.
Hassani Gravett scored the Gamecocks' final five points of the half to help South Carolina cut Alabama's lead to 40-33 at intermission.
Chris Silva, South Carolina's star forward, finished with nine points and four rebounds before fouling out with just under seven minutes to play. Silva had averaged 22 points and 8.7 rebounds in his first three SEC games.
Alabama won despite freshman guard Collin Sexton, the SEC's leading scorer, being held to a season-low five points.
The Crimson Tide's bench outscored South Carolina's reserves by 19 points.
It was the third straight win over the Gamecocks for Alabama, which eliminated South Carolina from last year's SEC tournament in the conference foes' most recent meeting.
The Gamecocks travel to Georgia on Saturday before returning home for consecutive games against ranked opponents, No. 21 Kentucky and No. 24 Tennessee.
Alabama heads to LSU on Saturday.
--Field Level Media
South Carolina | Alabama | |
Wesley Myers 15 | Scoring | John Petty 15 |
Justin Minaya 2 | Assists | Braxton Key 5 |
Maik Kotsar 5 | Rebounds | Donta Hall 7 |
Wesley Myers 5 | Free Throws Made | Braxton Key 3 |
Chris Silva 2 | Steals | Herbert Jones 4 |
Hassani Gravett 1 | Blocks | Donta Hall 3 |
Team | Points | FG% | 3PM-3PA | FTM-FTA | Assists | Rebounds | Blocks | Steals | Turnovers |
South Carolina | 62 | 35.8 | 5-15 | 19-25 | 8 | 26 | 2 | 3 | 13 |
Alabama | 76 | 58.8 | 7-17 | 9-14 | 18 | 34 | 7 | 8 | 16 |