Ash commands Pikachu to use Thunderbolt, but Gary tells his Eevee to use Double Team. Eevee performs the move, and Pikachu attempts to use Thunderbolt on all of them. As the illusionary copies vanish, Ash tells Pikachu to stop. Gary commands Eevee to use Take Down, while Ash commands Pikachu to use Agility; Pikachu’s attack stops Eevee in its tracks. As Pikachu attempts to use Thunder, and Gary has Eevee use Skull Bash. Eevee collides into its opponent, stunning Pikachu. Pikachu falls to the ground, weakened, while Eevee lands perfectly with no damage. Pikachu attempts to get up, but is unsuccessful and knocked out. Brock declares that the match is over, and Eevee is the winner. After both Trainers congratulate their Pokémon, Oak commends Gary on his training, after which Gary tells Ash that he did a great job before departing. Ash tells Gary that he will beat him next time.
(Source: Bulbapedia)