but can they do it under pressure in a real fight
For self-defense purposes these techniques work well.
They are not meant to be used (in fact cannot be used) in a cage fight like UFC or MMA.
Example where self-defense techniques are meant to be used:
A mugger attacks you on the street.
You kick him in the balls, side kick his knee or stick your fingers in his eye, punch him in the solar plexus.
All vital points.
This gives you time to escape.
You don't want to be rolling around trying to get an armbar on the street.