"Zoro, be careful not to win against Mihawk through better durability or better stamina, because otherwise you won't be able to prove you are a stronger swordsman than him."
Straight answer:
If King beats pre-King of Hell Zoro,
he wins because of his Lunarian durability and flames, not because of better sword skills.
Zoro had the better pure sword technique.
The reason he couldn’t finish it was that he couldn’t damage King.
Without the Lunarian healing and durability,
King loses to Zoro’s attacks (Tatsumaki and the others).
The fight is decided by the racial ability, not by who has superior sword skills.
Answer me, if King wins against pre KoH Zoro, is that because of his Lunarian power or sword "skills"??