Who won when Vaali fought Lord Hanuman ?
Vaali and his boon
In the Epic of Ramayana, we have heard of Vaali. He was a powerful monkey king who ruled in the southlands. Due to a boon from Lord Indra, no matter the opponent, half the power of the opponent would become Vaali's. This would help Vaali defeat anyone very easily.
Ravana's defeat at the hands of Vaali
Once Ravana heard of this power of Vaali and wanted to defeat him. But unfortunately, Ravana was defeated by Vaali. Due to this victory, filled with ego, Vaali now started boasting that there was no warrior on earth who could defeat him. He started challenging many warriors and defeated them eaily. Not many were ready to fight him due to his power.
Belligerent Vaali challenges Hanuman
Once Vaali met Lord Hanuman who was doing meditaion chanting Lord Ram's name and challenged him. Lord Hanuman smiled back at him. This enraged Vaali very much who now filled with rage said that he will defeat not just Lord Hanuman but also his Lord (Ram). When Vaali slipped his tounge, Lord Hanuman was enraged hearing Vaali's words. Both of them started preparing for a fight the next day.
Why did Lord Brahma Intervene ?
When the fight was about to start, a strange light appeared in the sky and Lord Bramha (The Creator) appeared before them. Lord Brahma instructed Lord Hanuman to use only one tenth of his power and to leave the reamining at the footstpes of his Lord.
Without any further questions, Lord Hanuman stepped in with only with one-tenth of his strength. Now, by the gift of the Vaali's boon, Vaali now got half of Lord Hanuman's power in him. Suddenly, Vaali could not bear the strength he got from Lord Hanuman. Vaali's heart started beating faster, he imagined his nerves cracking and bones breaking. Vaali was in immense pain due to the infinite power of Hanuman.
Lord Brahma appeared before Vaali and suggested he immediately leave the place and go far away from Lord Hanuman else his death would be certain. Vaali ran away immediately as far as he could. Slowly the power of Lord Hanuman drained from him. Vaali was now quite far from Hanuman and tired. Vaali started realizing his mistake.
Vaali realizing his mistake
Later, Vaali visited Lord Hanuman and asked to apologize him for his mistake. Lord Hanuman is considered as an incarnation of Lord Shiva himself whereas Vaali was just a human. Lord Hanuman remained a friend of Vaali and his brother Sugreev. This small story is not written in the epic Ramayan but has been passed down via oral traditions in many places. With this we understand how powerful Lord Hanuman really was. We dont know for sure how much is the limit for Lord Hanuman's Power.
