Including a follow jam by Quarterman and a jumper by Jordan Mickey, LSU closed the half with a 17-3 run to lead 35-24 at halftime.
Alabama won two of its last three games of the regular season by depending on strong defense. The Crimson Tide allowed only 56.7 points per game during that span, and the Alabama defense was focused on containing O'Bryant.
The powerful O'Bryant (6-9, 256) averaged 15.6 points and 7.9 rebounds in the regular season, but the Alabama defense collapsed around the junior every time he touched the ball in the first half. O'Bryant was limited to four points in the half.
LSU forced a turnover as Alabama tried to pass inside to O'Bryant to open the second half, setting up a 3-pointer by the Crimson Tide's Hale. Releford sank two free throws to cut the LSU lead to six points at 35-29. A free throw by O'Bryant and a 3-pointer by Jarell Martin, who had 10 points, quickly pushed the lead back to 10 points.
O'Bryant sank an open jumper to give LSU its big lead at 47-35. The Tigers led by nine points before Coleman and Stringer sank back-to-back 3s for a 65-50 lead.
"It was a tough, hard-fought battle," Jones said. "I thought our guys played well on both ends of the floor."