because zoro wasnt fighting kizaru, like, at all. He was getting carried around and then kizaru attacked him. No actual fighting happened. But fighting happened with enel and lucci and kuma.
At no point is Kuma besting Zoro, pay attention. Zoro is exhausted and cannot continue but Kuma never bested him.
Lucci kicked him through a wall isnt Zoro losing.
Once he reached Enel he was already in a bad state, that's not besting him either.
Gyukimaru could have blown air at him after Killer fight and he would have "bested him" him in your logic?