Suggested by Destroyer Flashman is very fast, but that’s simply not enough against Kakashi. Kakashi has the sharingan which gives him a considerable edge in combat. He has a ton of ninjutsu and is better equipped for a drawn out fight compared to the average combatant. Flashman is more of a 1 trick pony in comparison so it won’t take the ninja very long to copy and neutralize his abilities. Kakashi wins.