Hate to lower the tone here, but a classic self-defence move that can knock a man out, or at least make him lose interest in pursuing his agenda, is grabbing twisting and pulling his testicles until he passes out.
Doesn't work in real life. Nor does a groin kick. Every male from seventh grade on up has a reflex that blocks this attack, very effectively. Many women are taught to hit the solar plexus, jam a heel to the instep and kick a man in the knee or groin. Unfortunately, these rarely actually work and will enrage an attacker.
The real solution to the original problem is a taser or stun gun.
Jeff