With my very poor Russian, I’m pretty sure he says “ja jebu dolbojob” mockingly in Russian (meaning “I’m a fucking dumbass”), then I think the next might be “tupa mov vaflja, ce pizda” (“this cunt is as dumb as a waffle”) in Ukrainian, but I don’t know.

Edit: Upon re-listening I think it actually says “tupa mavpa bljad’, ce pizda” (“stupid fucking monkey, this cunt”). I like what I misheard more though :)