Whitebeard, Saint Shanks, Garp, Sengoku, Doflamingo, Crocodile, Luffy, Zoro, Aokiji, Kizaru, Akainu, the whole world far and wide that know Mihawk Recongnize his strenght lol. Not Just Vista. Even Kidd And Law accepted Mihawk greatness in the chapter Buggy become yonko.