Here it is.
Zoro is hit and stabbed by Killer. He's not stumbling afterwards. Instead, he stops Killer from pulling the scythe from his body. Does that sound like somebody who's going to fall from an attack. No, it doesn't.
Killer than attacks Zoro again which proves his attack didn't knock out Zoro because if it did Zoro would have fell immediately after and Killer wouldn't have needed to follow up with another attack.
Zoro attacks killer and blitz Killer. Zoro isn't it again and Killer falls. Killer is unconscious on the ground and Zoro is sbove him.
Their battle is over and Zoro won.