Daniel Cormier Warns Brock Lesnar, Stay Outta My Octagon!

Daniel Cormier says Brock Lesnar better not try to pull any cage-storming antics at UFC 230 ... because he ain't gonna be so nice this time around.

D.C. fights Derrick Lewis at Madison Square Garden on Saturday night -- and if Cormier wins, it sets up a possible superfight with Lesnar ... a fight they've been unofficially promoting for months.

Remember, after Cormier beat Stipe Miocic for the heavyweight title at UFC 226 back in July, Brock walked into the cage and shoved Daniel HARD -- and threatened to beat his ass if they ever fought.

"Brock Lesnar can come ringside," Daniel tells TMZ Sports ... "but he better not come in there because this time, it might be problem for him."

Might be tough for Brock considering he's headlining the "WWE Crown Jewel" event in Saudi Arabia on Friday night ... but it's theoretically possible for him to make it to MSG in time for D.C.'s fight.

As for Lewis, Cormier says he respects him as a fighter -- but at the end of the day, he's gonna beat Derrick's ass.

We also spoke with D.C. about a possible 3rd fight with Jon Jones and who he thinks Ben Askren should face when he makes his UFC debut.