Marcus Thornton scored 17 points to lead LSU to a 69-49 victory over Mississippi on Saturday.
The loss damages the Rebels' hopes of an at-large bid to the NCAA tournament.
Anthony Randolph had 15 points and 11 rebounds for the Tigers, who are now 10-16 overall, 3-9 in the Southeastern Conference. Ole Miss is 18-8 and 4-8.
It was LSU's first home league victory in six tries this season.
Chris Johnson had 12 points and 15 rebounds for LSU, while Terry Martin added 11 points.
The victory improved interim head coach Butch Pierre to 2-3 since he took over following the firing of John Brady. Both wins were SEC contests -- the other was at Florida on Feb. 13.
Ole Miss has four SEC games left.
It may have to beat Kentucky, Alabama, Arkansas and Georgia to get serious consideration for an at-large NCAA bid. Otherwise, the Rebels will have to win the SEC tournament in Atlanta in mid-March.