The defender's foot did deflect the ball but I understood the 'rules' were that they (the 'dubious goal panel') had to be 100% certain that the ball wouldn't have gone in the back of the net without the defender's intervention.
Looking at the replay footage, I can't see how anyone could be "100% certain" that the ball wouldn't have gone in, which would tend to suggest that maybe I/we don't understand the rules that the panel are duty bound to abide by. Perhaps they don't have to be "100% certain" and are allowed to use their discretion and/or an element of probability or gut feel?
Does anyone know for sure what "rules" the panel are instructed to adhere to?
That said, I still think its harsh to deny Mane the goal, whatever the rules might say.