Travis Scott took a nasty fall Saturday night during his performance at the Rolling Loud festival ... a fall that messed up his knee something bad.
Travis was performing "BUTTERFLY EFFECT" at Citi Field in Queens when he jumped up and landed wrong on his right knee ... then tumbled to the ground.
Kylie's ex was clearly injured and could barely move around the stage. He ended up staying in the same spot, as members of his crew jumped on stage to check on him.
Travis told the crowd he thought he broke his knee, but nonetheless the show went on. He told the crowd, "Nothing can ever stop this show."
Travis completed his whole set while standing in one spot on stage for the rest of the concert. So far, no word on the extent of his injury.