If Lucci goes "The hell? How are his attacks as strong as Straw Hats???" or something similar I'll lose my mind.
Lucci isn't some normal fight for Zoro. Zoro actually liked Kaku, to an extent, or at least had respect for him. Zoro can tell Kaku is a decent guy who got roped into the wrong thing against his will, his post-battle convo with him was respectful in Enies Lobby.
Zoro hates people like Lucci who have no respect for life and death, and, despite what a lot of people think, Zoro doesn't like it when women get hurt nearly as much as Sanji does, because of Kuina.
Zoro also is very familiar with Rokushiki at this point. Ain't no way Lucci is surpassing King's defenses, IMO.
Lucci isn't weak at all, either, but Zoro and Luffy just defeated two pirates who had been active for multiple decades and had barely ever received any physical damage.
If anything, someone will save Lucci from Zoro, probably some Vice Admirals.