First of all, levels are irrelevant, so stop with that "level 5 Snivy beated level 100 Pikachu" nonsense. And no, that School of Hard Knocks episode was way too early and was not mentioned since.

And second of all, Pikachu was zapped by Zekrom. Sure, you could argue that he could've still used Quick Attack and Iron Tail, but has it crossed your mind that it also sucked out Pikachu's energy in general? Pokemon can have their on-and-off days.

And while bad writing has practically played a part of the entire anime, I'm sick of the overall ignorance towards the Pokemon anime in general, especially when people use game logic.