I get what you mean..but Gai won't go down as easy as that
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It's not just his feet..he looks at his body as well
Remember Ay was looking at sasuke and was still able to avoid amaterasu...7th gates Gai is on par with V2 Ay in terms of speed considering his movements aren't human according to Gaara and he was able to attack Madara that fast when Minato got easily reacted to
Don't get me wrong I'm not saying Gai wins..I'm just saying gai won't go down that easily considering the way you're looking at it...I'll say sasuke probably wins this due to his susanoo and nothing else