Do keep in mind that the Genesis Driver is the perfected model of the Sengoku Driver. In the hands of a skilled (or insane) user, it's very much plausible that Zangetsu Shin can take on Kiwami Arms, just like how Duke took on Gaim and Knuckle without too much trouble. True that Kiwami Arms originates from the Forbidden Fruit, but it's used via the Sengoku Driver, a mere prototype and that's more or less a handicap that gives a Genesis user a fighting chance.
Next factor is Kota...my god...nigga held back so much even if he did go Kiwami with Baron as support, his hesitation just upped Micchy's chances for victory.
I will agree on one thing, Micchy's completely lost it.