Whoever scores first will still keep staying in South Africa. If Japan strikes first, they will control the flow of the game until the end. Japan has played pretty good defense and done a good job of pressuring opponents on the midfield. If Denmark does it, it will be a disaster for Japan. They will have to push their backline forward to equalize but don't have any threat to score 2 or more goals. Being as a underdog, constant push up front will eventually result in another goals conceded.