Rapper Lil B -- I Won't Lift Kevin Durant's Curse ... Until He Plays Me In Basketball

Kevin Durant actually has bigger problems than being out indefinitely from the NBA ... 'cause rapper Lil B says it's his "BasedGod" curse that's dogging Durant ... and it won't be lifted until Kevin sees him on the court.

The beef between the two started back in 2011 when Lil B says Durant took an unprovoked shot at his rapping skills in a tweet.

Lil B then fired back with a tweet of his own ... hitting Durant with the dreaded "BasedGod" curse and proclaimed that Kevin would never win a title until it was lifted.

So when the news dropped that Durant's foot injury -- which has hampered him all year -- was going to keep him off the court indefinitely, social media began buzzing ... was it the curse?

TMZ Sports spoke to Lil B and he told us Durant's BasedGod curse remains, and it's the reason for all of KD's current career struggles.

"He's still under it. Everyone who disses Lil B pays for it."

According to Lil B -- who dropped a hilarious song called "F*ck Kevin Durant" last year -- there's only one way to break the curse ... Kevin has to play him in basketball.

"All he has to do is meet on the basketball court for a friendly game of 21. I'm passionate about my game, my defense, if he doesn't beat me 21-0 he should be embarrassed."