Dodge and be quick, they'll be a-falling.
They're off balance when they miss.
Miss what? You don't go off balance when you give a straight hit and miss. Have you ever fought before or is it me misunderstanding?
It's experience, and physics.
When they hit straight, and you duck (quack), they hit air. Air usually doesn't help you with keeping balance. It's only a short time, but they're off-balance. In that time, kick their kneeholes, or simply tacke/slide them. Guaranteed they will go down, unless they are Really, really good.
And if they do a sideattack, Duck again, and punch them 2 times just below the ribs, a bit to the left or right, you'll punch the air out of their lungs, and if you put your weight behind it, you'll hit, n matter what they can deal with.
Fight dirty, you win.