?? What defense, as in, King can't get closer to Fujitora or what?
If that's what you meant, single flying slash is all what it takes.
Even if Fuji puts King under gravity pressure, Zoro manages to break free then counterattack with flying slash, so will King.
And again, once Fuji is busy blocking, his gravity is cancelled. From now on, it becomes worse and worse for Fuji because King the type that won't give the opponent to breath.