1st Ever Robot Master You Beat in the Classic Mega Man Series?

Who Was the 1st Ever Robot Master You Beat in the Classic Mega Man Series?

I'm sure he wasn't the 1st but my earliest vivid memories started around Mega Man 8 with Clown Man.

My brothers & I used to pass the controller time after time playing Classic Mega Man lolz. But I was too young to remember specific details. I wonder if we ever actually did beat one? Lolz We must have.