Black Panther, After a very very tough fight.
T'challa is a Tactical genius, like Slade...he maybe don't have the brain processing speed of 9 times of a human, but his scientific knowledge definitely gains him a chance. I don't understand why so many people think Slade can easily beat BP.
T'challa 's Vibranium suit and herbs gains him the strength to go Toe to Toe with Deathstroke. I am gonna go with BP here.