Taken from EP36 of (Actually) Abridged:    • I (actually) abridged Pokemon Episode...  

Riding high off of accidentally defeating Team Rocket in a complete fluke 4 episodes prior, Misty's Psyduck enters it's first real Pokemon Battle against an enemy trainer.

(PS: I don't consider EP 32 a real battle because Team Rocket never even bothers to attack Psyduck - they're just dumbfounded by it the entire time)