Am I the only one flabbergasted here by the sheer size of Hashirama's summon? That thing makes Kyubi seem like a pet cat in comparison. What monstrous chakra levels he must possess to summon that and fight. Suddenly, Kyubi seems weaker in comparison. And we thought Wood Dragon was overpowered.

Minato wouldn't stand a chance. All he could do is use his space time barrier technique to send the summon's attacks or the summon itself to another place. The only way I see him winning is if he used some of the Uzumaki fuuinjutsu to incite a handicap on Hashirama, as he is just far too strong otherwise.