Use Super Cancel to obstruct the opponent's run
Super Cancel (R1+R2) is very important while defending since it gives you complete freedom while moving your player. Sometimes you don't want to be running in a straight line towards the ball, and Super Cancel enables you that in PES.
In some situations, you may want to get in the way of an opponent so that he can't reach the ball, especially when your player lacks pace but has good physical attributes.
In this clip, I'm using Super Cancel while running towards the ball to block my opponent. Since I'm in front of my him, I am certain I will reach it first. His pace is useless, and unless he's a very strong forward, charging won't make a difference.