Sparring match video a knockout

A new video on YouTube certainly packs a punch. It shows a Korean amateur boxer sparring with a man on a street.
The video starts with the man trying to hit the boxer, but most of the punches miss or are blocked.
With no damage done, the boxer finishes the fight with one punch. The tap to his face just before the punch is a signal “the boxer will hit that part the face so be careful.” Anyway, it is going to take some time before the man spars with another boxer.