I take back what i said, my friend pointed something out to me in why itachi would lose,1st itachi has no way to keep up keeping up with minatos base speed, and his reflexes are to high to be hit by genjutsu, and i never thought of this before but flying thunder god be used to counter genjutsu, because if itachi cast a genjutsu on minato even if its tsukiyomi,in reality minato can just simply teleport his body to a different location and itachi will no longer have a target their for genjutsu.