Pokémon : S3 | E36 – Hot Matches!

After exiting the Pokémon Center, Ash bumps into a young Trainer holding a Growlithe in his hands. He warns Ash to avoid an old mountain bridge because of a tough Trainer, but Ash decides to go anyway. As the group discusses which Pokémon the Trainer might be using to be so tough, Team Rocket overhears the conversation and decides to snatch the Pokémon once they are weakened during the battle. Once they reach the destination, Misty spots a young girl. When Brock begins flirting with her, she identifies herself as Miki and challenges him to a battle, surprising Brock with her determination.

Miki instructs Brock to send out a Fire-type Pokémon, explaining she is trying to get her Skarmory to be stronger and beat any type of Pokémon; even its weaknesses like Fire-types. Miki sends out Skarmory while Brock sends out his only Fire-type Pokémon, Vulpix. The battle starts with Skarmory making a dust cloud in Vulpix's face while it swoops back into the air. Before Skarmory can attack, Vulpix uses Flamethrower, only to miss because of Skarmory using Agility. Vulpix then starts using its own Agility to flee from Skarmory. However, Skarmory strikes it with Steel Wing, and Vulpix is knocked out. Miki asks Brock if he has any more Fire-type Pokémon. Ash steps in and says that he has one, but he boasts that it might be too hot for her Skarmory to handle.
(Source: Bulbapedia)