Flau'jae Johnson ain't just getting LSU wins with her skills on the court ... Mikaylah Williams tells TMZ Sports her music's helping fuel the Tigers' postseason run too!

Kim Mulkey's sophomore guard sat down with us on Monday while working a ceremonial shift at a Raising Cane's in Baton Rouge ... and she made it clear, Flau'jae's tunes are a big part of LSU's success this season.

She told us the Tigers bump Johnson's music in the locker room regularly -- and get this, she says it's played so often, they know all the lyrics!!

"We all love her music," Williams said.

Johnson, of course, has been rapping for years -- and has flashed so much talent, Lil Wayne actually collaborated with her on "Came Out A Beast." It seems her beats have some good luck mixed in them as well ... because LSU is 28-5 this season, and is considered one of the biggest favorites to win the 2024-25 natty.

The Tigers will have to wait a bit longer to find out who they'll play in the upcoming NCAA tournament -- but while the delay might cause a bit of anxiety, it's sure appreciated ... as it'll give Johnson some more time to rest an injured shin that's kept her out of recent LSU games.

Williams told us the team learned a lot in Johnson's absence ... and she's sure when the guard gets back to full health by the time the tourney rolls around, LSU will be ready to rack up some victories -- and dance to some Johnson bars afterward!