selective focus photography of adult fawn pug

I was shooting a birthday party on a hotel on a sunday morning. One of the guests had this very happy and eletric dog, I tried to take a picture of him for hours but could not have stopped for nothing. I was tired of chasing that dog, and out of nowhere he strike this pose, I grabbed my 18mm f.2, put it on my camera took the shot on a fraction of a second and the dog ran away as i was looking at My camera’s screen to find that finaly got a decent shot.