Seeing as Law cannot use his Devil Fruit, I'd give it to Mihawk mid-high difficult. According to my guesses, Doflamingo (without awakening) is more or less = with Law + Luffy (without g4) fighting together. Mihawk is stronger than even awakening Doflamingo and Law wouldn't be of much use here without his fruit.
Hell, even if Law had his powers, I'd wager Mihawk would take this, albeit with great difficulties.