Definição e Significado de "[draw] first blood"

What is the origin of the idiom "draw first blood" and when to use it?

The idiom “draw first blood” is believed to have originated from the practice of hunting, where the first person to draw blood from an animal was considered to have made the first successful attack. It has been used metaphorically since at least the 17th century to describe gaining an initial advantage over an opponent. The phrase also has a strong association with boxing, where drawing first blood would signify scoring a victory over someone. Over time, it has come to describe any situation where someone gains an early advantage in a competition or conflict