In Yu Gi Oh East AcademyDavid utterly destroys Denero in his first duel. Proving himself to be more than just some fanboy.
And before that was Marcus's duel against Denero's father. Every move the latter made only served to help Marcus's strategy. Which cultimated in him finishing off the culitst with a casual One-Hit Kill.
Amanda vs. Sam Sinister and the Brickster in the subway station, and Frozeen and Libo vs. Lord Vladek in the subway tunnel. The villains never stood a chance.
Rex vs. French Fries and Pharisee vs. French Fries. In both instances, French Fries was soundly curb-stomped.
Pharisee vs. Trigger was actually a subversion. For most of the fight, it was definitely a Curb-Stomp Battle, as Pharisee easily overpowered Trigger in the fight. However, it was ultimately subverted because Trigger knocked out Pharisee in the end, emerging as the victor of that fight.