UFC Contender Jamahal Hill Says He Wants To 'F*** Up' Volkan Oezdemir

"I can't have people speaking out. If you're gonna speak my name you better be sure. [Volkan Oezdemir] spoke it, so now I'm gonna make an example out of him."

That's #10 ranked UFC light heavyweight Jamahal Hill -- fresh off a first-round knockout of Johnny Walker at UFC Fight Night -- calling his next shot ... declaring he wants to fight #8 ranked Oezdemir.

"I've already said it, bro. As long as I got the say so, [Volkan's] next."

But, why are the guys beefin'?

After Hill's impressive knockout of then #10 ranked Walker, Jamahal called out his doubters. Oezdemir responded to a Tweet about "Sweet Dreams," writing "I'm still doubting [Hill]"

And, that isn't sitting well with Jamahal.

"Bro, he really don't understand. And, it's not like I'm emotional or taking it a type of way, it's just now I really wanna f*** you up so now my focus is on that."

FYI, Oezdemir has lost his last 2 fights ... but has been in the cage with some of the baddest men in the world. Volkan has wins over Aleksandar Rakic, Ilir Latifi, Jimi Manuwa and Ovince St. Preux.

There's more ... we also talked to Hill -- who says he's going back to the gym Tuesday -- about his time inside the Octagon with Walker. JH says Johnny has all the physical tools ... and it's clear Hill doesn't believe Johnny is washed.

"Physicality. He was huge. He felt like he was about 225. He was a big dude. Also, his mental prowess is a lot higher than people give him credit for."

Hill had a final message for Oezdemir ... let's do this.