You mean his best shot in a weaken and poor condition that still scarred Kaido and out performed Luffy after his mid battle growth.
Zoro is still getting used to his sword. He even stated he would be stronger by time he got used to it. Luffy should be lucky Ods had the weaker Zoro, if not he would probably still be fighting him. If Zoro can create an incredibly large and powerful barrier haki ro stop Hakai he could definitely use that same power and skill to create smaller barrier haki to clash with Kaido weaker attacks. Of course, he would have been able to use asura mode longer and more if he was in better condition.