Um, as someone who has studied martial arts... that’s the point of kicking him in the groin first: to line him up for the shot to the face.
Standard tactic #1 for getting someone larger than you to bring their head down to the height where you can get the real damage done: nail him in the groin. The natural reaction is to pitch forward - it’s automatic.
Works whether the assailant is coming at you from the rear or the front, too. Lots of the techniques taught to get out of a strangle or bear-hold from behind start with rotating your hips out of the way and nailing him right square in the nuts. His head comes forward, your head goes back - lather, rinse, repeat. Pretty soon, he’s grown rather disabused of trying to contain a smaller person.
I can’t even remember how many moves start with “a swift kick to the nuts.” The next move varies all over the map - knees to the face, feet to the face, elbows to the back of the head, fists boxing in the ears, knee to the face and elbow to the back of the head at the same time, you name it.
Just out of curiosity, what do they tell you to do if the attacker is a woman?