The Bulldogs saw a 17-point first-half lead evaporate, then saw Justin Hamilton and Anthony Hickey finish the job in the Tigers' 69-67 overtime win at Pete Maravich Assembly Center.
Hickey's layup put the Tigers up by four points with 23 seconds left in OT, but MSU got a 3-pointer from Renardo Sidney with 12 seconds. Then Brian Bryant stole the inbounds pass and was fouled.
He hit the first free throw to tie it at 67 but, after an LSU timeout, missed the second.
Hickey, the freshman point guard who nearly brought LSU back in a loss at State earlier this year, sliced through the lane for the game-winning layup with 1.4 seconds left.
"I know you guys magnify the last play. Just one play of 65," MSU coach Rick Stansbury said. "There's 64 other ones we can make somewhere else, and that's not as important."
It was the second consecutive overtime loss for MSU (19-7, 6-5 SEC), which fell to Georgia on Saturday. It's also the first time this season State has lost back-to-back games.
"It hurts," MSU point guard Dee Bost said. "That's what it's like on the road. It's tough. We can't blame nobody but ourselves. ...
"We played the game, we blew the game, we gave it up."
Hamilton, who was quiet in the first meeting - a 76-71 State win - scored 14 points for LSU (15-10, 5-6). The forward's 3-pointer tied it at 61-61 in OT, then his dunk made it 63-61.
Ralston Turner scored 17 to lead LSU, while Storm Warren and Andre Stringer had 10 apiece. The Tigers shot 41.5 percent, including 5 of 19 from 3-point range.
State hit 45 percent from the field and 6 of 18 from deep. Bost had 15 points, five assists and five turnovers. Rodney Hood had 14, Sidney 13 and Arnett Moultrie 10 with 11 rebounds.
After two Hamilton free throws tied it at 58-58 with 41.6 seconds left in regulation, MSU had the ball with a chance to go ahead but turned it over on a charge by Moultrie.
Hamilton missed a 3-pointer just before the horn.
MSU jumped out early, taking a 30-13 lead by the 5:57 mark of the first half. Bost hit a trio of 3-pointers to cap a 25-8 surge, giving him 13 points at that juncture.
LSU, which hit only 6 of its first 20 shots, starting finding the basket. It closed the half with a 16-6 run, cutting State's lead to 36-29 on Turner's 3-pointer at the halftime buzzer.
Six different players scored for LSU during the run, which continued into the second half when the Tigers scored the first seven points to tied it at 36-36.
MSU's scoring drought of 5:36 was halted by a Sidney bucket at the 16:28 mark. That sparked a 10-1 run by State, as LSU couldn't score a field goal for a span of 5:31.
Again LSU responded, behind Turner.
He scored seven points during a 17-6 run, then got the assist on Storm Warren's go-ahead layup, making it 52-50 LSU with 6:43 left.