I'd say Luffy defeated Kaido, he flat out overpowered him and there was even a panel of Kaido saying he beat him. He also looked to be either unconscious or very close to it (life flashing before his eyes) after the punch and was knocked out of his dragon transformation.
Big Mom was clearly not defeated in the same way, Oda pulled some Whitebeard level shit with her defeat, in fact I would say his heart attack was even less bullshit. He nerfed her to an unbelievable degree and the ocean did the rest. It was King all over again.