Khamzat Chimaev SMASHED another opponent just 4 days ago ... but the UFC phenom says he's ready to fly to Fight Island and fight Israel Adesanya or Paulo Costa for the title.
TMZ Sports talked to Chimaev ... and asked if he'd fight Adesanya or Costa this weekend in Abu Dhabi if either of the men where unable to participate in the UFC 253 main event.
That might sound crazy ... until you consider the 26-year-old undefeated fighter fought and won twice -- only 10 days apart -- back in July.