In all of Onigashima the only thing Law has done in close to one vs one circumstances is this
Where yes, Kid attacks first, but it’s Kaido who then initiates the attack on Law, who dodges and gets Gamma Knife.
Everything else Kaido or Big Mom have been focusing on someone else, paying no attention to him or it comes as a combo following someone else’s attacks. Law’s best, most recent one vs one feat onpanel is still when he had a stalemate with Hawkins in Act One lol.