The victory completed a three-game SEC series sweep for the Rebels, who improved to 26-15 overall and 10-8 in league play.
LSU, which was swept on the road for the first time since 2001 at Arkansas, fell to 26-16 overall, 6-12 in the SEC.
The Tigers return to action at 6:30 p.m. Wednesday when LSU plays host to the University of New Orleans.
"We just have to keep working and teaching to get this young club back on track," said LSU coach Smoke Laval. "This has obviously been a rough stretch, but we still have a chance to recover and move forward."
Ole Miss catcher Justin Brashear led off the Ole Miss eighth with a homer off of LSU reliever Chase Dardar to tie the game at 8-8. Dardar then walked second baseman Justin Henry before he was replaced on the mound by Will Harris.
Harris gave up consecutive singles to C.J. Ketchum and Chris Coghlan to load the bases before shortstop Zack Cozart delivered an two-run double to give the Rebels a 10-8 lead.
Right fielder Mark Wright later added a sacrifice fly to increase the advantage to three runs.
Catcher Matt Liuzza and third baseman Buzzy Haydel started the LSU ninth with consecutive singles, but Ole Miss reliever Cody Satterwhite retired the next three LSU hitters to end the game.
Sattterwhite (5-2) picked up the win, allowing no runs on two hits in two innings with one walk and no strikeouts.
Dardar (5-2) charged with the loss as he surrendered three runs on three hits in three innings with three walks and three Ks.
LSU trailed 6-2 before scoring five runs in the top of the sixth to take a 7-6 lead. The Tigers were aided by three walks and an Ole Miss error, and pinch hitter Jason Ogata's two-run double highlighted the rally.
The Tigers increased the lead to 8-6 with a run in the seventh as centerfielder Jarred Bogany lined an RBI single.
Ole Miss closed the gap to 8-7 in the bottom of the seventh on DH Jon-Jon Hancock's run-scoring single, setting the stage for the Rebels' four-run eighth.
Break out the brooms: Tigers swept
Tiger Blitz Top Stories
LSU Spring Position Recap: QuarterbacksSpring practice for the Tigers is in the books. Tiger Blitz takes a look at the current state of the LSU quarterback position.
Tiger BlitzYesterday at 1:10 PM
4-star LB high on the Tigers, othersScout 300 inside linebacker Ayodele Adeoye is quickly becoming one of the hottest recruits in the nation. With an offer from Texas on Tuesday he has seen his list grow to 23 offers…
Scout FootballYesterday at 11:45 AM
2018 athlete recaps LSU Spring Game visit2018 West Monroe (La.) athlete Slade Bolden took in LSU's Spring Game on Saturday and talked about the new offense and where his recruitment stands.
Tiger BlitzYesterday at 8:27 AM
LSU offers familiar 2019 big man for Wade2019 Richmond (Va.) Trinity Episcopal power forward Armando Bacot picked up an LSU offer this weekend after a solid performance in Dallas.
Tiger BlitzYesterday at 7:19 AM
Recapping LSU Basketball's first Eval PeriodWill Wade's staff was on the circuit watching plenty of prospects and handing out offers during the first eval period. Tiger Blitz recaps LSU's weekend in basketball recruiting.
Tiger BlitzMonday at 12:55 PM