Pokémon — Episode 77: Round One - Begin!

You are watching the episode Round One - Begin! Ash enters his first match of the tournament on the water field against Mandi the Astounding. During the battle against Mandi's Exeggutor, Ash's Krabby evolves into Kingler, who he then uses against Mandy's remaining Seadra and Golbat, winning the match and moving onto the next preliminary round.