Pokémon : S5 | E58 – Love, Pokémon Style

The day after the opening ceremonies, at the Athlete's Village Pokémon Center, Ash discovers that he has been grouped into Group H. Brock further explains that the semi-final round is a round-robin tournament, where each Trainer battles the two others—with three points for a win, one for a draw, and none for a loss. The Trainer with the most points in the group stage will move on to the Victory Tournament. Ash is confused by the details but hopes to win anyways.

Heading back out, they come across Ash's first opponent, a young girl named Macy. The two help each other get fired up, nearly getting into a battle in doing so, but just as it begins, Pikachu and Macy's Vulpix are snagged by Team Rocket in nets. As the Rocket trio makes their getaway on a tandem bike, Ash and Macy pursue them downhill. Macy soon trips and falls over, though Ash manages to break her fall. He tells Macy to leave recovering the Pokémon up to him, Macy is immediately smitten with Ash. Meanwhile, Ash cuts off Team Rocket, and has Bayleef recover the stolen Pokémon and send Team Rocket flying with Vine Whip.
(Source: Bulbapedia)