You were in the "void" where action takes place outside of thinking, or even consciousness. You don't need to know what you did or how you did it. "Knowing" how to do it again, or perhaps more accurately, allowing yourself to do it again is another matter.
I've experienced this too a few times, like sparring in a tournament and suddenly, in a flurry of action, finding myself at the guy's back firing punches to the back of his head, having no idea how I managed to get there.
It's a small taste of what's possible in MA when mind, body, spirit (and luck?) are all in alignment.