Cerrone throws his lead hand out as he switches his feet, forcing Guillard to focus on Cerrone's hands and upper body. Notice how Cerrone's hips in the first still are already quite square and are almost reversed in the second still when he switches. Then in the third still notice how his hips are turned all the way into the kick. Notice how his kick ends up on the other side of Guillard's head once he has connected - showing just how committed his hips are to the kick.
And wallop.......here is is