Why do some attacks go through others?
I'm new to the game and did a random on random CPU match (lv 9), and I got dk against jigglypuff. There were several times when I would use a down air and Jigglypuff would use up-air, and every time the CPUs attack would land and override mine. This is far from the first time this has happened where my attacks would ALWAYS get overridden in a specific situation, so can someone explain what's happening and how to learn from it? I know about the 9% rule, but I highly doubt that applies here, so why do some attacks always override others?