The entire fight with CoC was King of Hell obviously, which is overusing Haki to a point of Zoro pointing out he will die if it drags on for too long. Also, yes, it is base Zoro, but Zoro's base due to not having many upgrades (King of Hell, Asura) is stronger than Luffy's base, while Luffy compensates by having more forms down the line, on top of having ACoC.
This isn't lucci in base is it