Pokemon League Gate Rival Battle

Walkthrough
After obtaining all eight Gym Badges, it is time for you to head off in the direction of Indigo Plateau in order to battle the Pokemon League. You begin this trip by heading west of Viridian City on Route 22, since Route 22 connects to Route 23 (which contains the Pokemon League Gate & Badge Checkpoints), and then Route 23 connects to Victory Road followed by Indigo Plateau.

But right before you exit Route 22, your Rival will again appear and challenge you to a battle. He, too, has obtained all eight Gym Badges, and he also intends to challenge the Pokemon League. His team has greatly improved since you last saw it at Silph Co, having four fully evolved Pokemon that each reach at least Level 50. After defeating him, he will mention how he always felt that he needed to look after you along your journey, but that has now changed based upon your current level of skills. He will then go ahead of you towards the Pokemon League.

Pokemon Trainer Rival
Level 50 Pidgeot: Quick Attack, Air Slash, Sand Attack, Roost
Level 50 Vileplume: Petal Dance, Toxic, Acid
Level 50 Marowak: Focus Energy, Bonemerang, Thrash, Swords Dance
Level 51 Raichu: Thunder, Quick Attack, Thunder Punch, Slam