It wasn't that there were no dark horses who defeated the strong in martial dao competitions. It wasn't that there had never been a precedent of a peak Emperor Realm cultivator defeating a Great Emperor.
Although there were very few of them, the world of martial dao was full of wonders. There would always be some special geniuses who triumphed over the strong and challenged those of a higher level, or even swept away their opponents. There had been no shortage of such cases in history.
However, this kind of thing was a minority in the end. It was as rare as phoenix feathers and qilin horns. Usually, every time it appeared, it would be greatly exaggerated and become a topic of conversation and inspiration for the weak. It would be widely spread by others.
Generally speaking, such an example would be called a miracle.
Pill King Hui was indeed outstanding in terms of overall strength, but he wasn't someone who could create such a miracle in martial dao.