LSU (35-24) won three of its five meetings against the SEC champion Crimson Tide this season.
LSU will await an NCAA Regional bid when the 64-team bracket is unveiled at 11:30 a.m. Monday on ESPN.
The Tigers outhit Alabama nine to eight and had several chances of putting together their 21st comeback win of the season Friday, but LSU committed five errors, walked 10 batters and stranded eight runners on base.
Centerfielder Jarred Bogany went 2-for-4 and scored two runs, and left fielder Bruce Sprowl provided two RBI.
"We hit the ball pretty hard today," said head coach Smoke Laval. "We hit it probably harder than they did, but we walked 10 batters and had five errors."
Alabama right-hander Tommy Hunter (10-3), the program's leader in freshman single-season wins, scattered eight hits and three runs, walked one and struck out a career-high eight hitters.
He was aided by a three-run first inning on the first of the Tigers' fielding blunders.
Shortstop Michael Hollander booted centerfielder Emeel Salem's ground ball on the first pitch of the game. LSU starter Chris Cahill then proceeded to walk the next two batters and nearly found his way out of a bases-loaded jam courtesy of runner's interference.
Catcher Kody Valverde rolled a double-play groundball to Hollander, who flipped to second baseman Buzzy Haydel. Haydel was then taken out by designated hitter Alex Avila at second, which forced the second base umpire to call runner's interference.
Salem, who crossed home, was required to go back to third, and Cahill was one out away from ending the inning with no runs. However, second baseman Evan Bush connected on a timely hit with a two-run single to center.
LSU committed its second error of the inning when Bogany misplayed Bush's single. Two batters later, Alabama scored its third unearned run on an RBI single by right fielder Kent Matthes.
Cahill (1-1) exited after only working 0.2 innings, allowing two hits and three runs -- all unearned -- en route to the first loss of his career.
Senior right-hander Chase Dardar kept LSU in the game with a solid relief outing as he blanked the Tide in the second and third.
The Tigers got on the board in the bottom half of the third on a one-out single by Sprowl, scoring Bogany, who had reached on leadoff single.
Dardar suffered some tough luck after third baseman Will Harris committed the Tigers' third error on right fielder Kent Matthes' groundball to lead off the fourth. Matthes came into score two batters later on Salem's RBI single, pushing the Alabama advantage to three runs again.
The Tide tacked on another run in the fifth on an 0-2 RBI single by third baseman Spencer Pennington, and Valverde blasted his 11th homer of the year with a solo shot in the seventh off of Dardar.
LSU had its chance at a comeback in the seventh as Hunter became fatigued. Designated hitter Jordan Mayer and Bogany provided back-to-back singles, and Haydel converted an RBI opportunity when he reached on an error by shortstop Greg Paiml.
After Sprowl cut it to a 6-3 deficit on a sacrifice fly, Hunter walked Hollander, and Alabama head coach Jim Wells summoned junior Jake McCarter from the bullpen.
McCarter, who worked two innings against the Tigers on Wednesday, induced a fly-out from Liuzza and then fanned Stewart with runners at the corners.
Harris tossed the final two innings for LSU, surrendering two runs on two hits and walking a career-high three batters.
McCarter hurled 2.2 scoreless innings of relief to qualify for his first save.
Tigers knocked out of SEC Tournament
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