Oh man... I don't have a specific moment, because combat sports have been the only sport I've ever watched.
Early on I was a boxing fan and things for me evolved into watching karate, kickboxing, and the UFC.
I was always a fan of martial arts, and Bruce Lee was the reason for that... I took judo and wrestling when I was a child because I wasn't very tall... and living in New York, I always seemed to get into fights when I was young.