KSI's fight with Logan Paul is set to be one of the biggest sporting events of the year ... but the British YouTuber says he's got even BIGGER plans in mind ... telling TMZ Sports he's dead set on going pro!!
We spoke with KSI -- who more than 19 MILLION subscribers on YouTube -- about the August 25 fight in Manchester, and he says he's not putting on an act ... his hatred for the Pauls is VERY real.
"I think his ego needs to be put right down." KSI says. "He thinks he's the sh*t and I'm about to f*ck him up and literally put him in his place."
"I want this year to be the worst year of his life, 100%. Pretty much, I want to squeeze every bit of relevancy from him and then move on to my bigger goal, which is to go pro."
We also asked KSI what he thought about our video of Logan knocking a dude on his ass in a recent sparring sesh ... and his response is hilarious.