Hold down B with your captain in your attacking half to activate the super strike. You will then press B twice on a needle to see if you can get the ball in. If you can get it perfect, it is a certain goal. A Super Strike goal is equivalent to two normal goals.
The Super Team will be the final foe for you at the end of the Bowser Cup. They are capable of using a Super Strike with anyone of their teammates, so watch out. You will unlcok them for play if you can beat them.