If you fall backward, here is a simple breakfall that allows you to fall backwards while protecting your head.
Bend your knees, tuck your chin towards your chest and roll backwards, landing on your butt first.
When your back hits the ground slap both palms downward on the ground while keeping your head tucked in. This will displace the impact of the fall.
If your attacker approaches you while you’re down, you can always use your legs and deliver flashbangs to his knees, thus distracting him enough so that you can get back on your feet or escape the situation.