The popular YouTuber has uploaded a video to his channel which shows back-to-back matches against the rival rapper, as the pair have previously created diss tracks about one another. In the first game, KSI decided to play with the team he supports, Arsenal, and Quadeca chose the Belgium national side.
However, the rather uneventful game ended in a 1-1 stalemate, with both players expecting more from themselves in a rematch. The second leg, though, got very heated indeed.
Quadeca stuck with Belgium in game two, but KSI decided to switch it up and started the game strong with Barcelona, dominating possession with some brilliant intricate play in the opening five minutes.
"The beautiful game. The beautiful game! Oh bro, I'm coming!" he screamed, before unleashing a primeval roar to the camera.
Moments later, Romelu Lukaku gave his opponent the lead after heading it past goalkeeper Marc Andre Ter Stegen to make it 1-0.
It was all downhill from there. He conceded another two soon after - Kevin De Bruyne and Dries Mertens with the goals - leaving the YouTuber utterly dumbfounded.
Having claimed to have had hardly any experience on this year's FIFA game, KSI pointed out a few key moments where he'd just passed the ball straight to the opposition and it was ultimately his undoing in this hilarious video.
"This game is fucking trash. This game is fucking shit. Fuck this game bro, it's dead" he said after Mertens walked through the Barcelona defence to score the third. "This game is dead. I ain't playing this again. It's legit the worst FIFA, the worst FIFA I've ever played."
KSI was awarded a penalty with a minute left to play, giving him a chance to salvage something from the game, but missed.
Afterwards, Quadeca took the victory and rejected a rematch from his rival.