Law showed in Dressrosa that he could match Doflamingo’s attacks with just his sword. Doflamingo’s string have cut apart giant masses of land and hurt stronger characters than Law before. Even some of Law’s moves like tact (which moved objects with enough energy to yield similar values), counter shock which hurt Vergo and Doffy badly, etc. Law has the feats to be able to match somebody like Zoro, if anything Law scales upwards over Zoro due to his portrayal with Luffy and Kid, they have grown just like Zoro has.