I just swept someone with a Pikachu
I send in Pikachu, they send in Smeargle.
Turn 1
Smeargle uses Fake Out and doesn't do very much damage.
Pikachu flinches.
Turn 2
Pikachu uses Substitute.
Smeargle uses Endeavor - it fails.
Turn 3
Smeargle uses Detect.
Pikachu uses Thunderbolt; Smeargle protects itself.
Turn 4
Smeargle is switched out for Snorlax.
Pikachu uses Thunderbolt - around 1/3 damage.
Turn 5
Pikachu uses Thunderbolt - around 1/3 damage again.
Snorlax uses Return, breaking Pikachu's substitute.
Turn 6
Snorlax is switched out for Spiritomb.
Pikachu uses Thunderbolt - just over half damage.
Spiritomb recovers HP with Leftovers.
Turn 7
Spiritomb uses Protect.
Pikachu uses Thunderbolt, but Spiritomb protects itself.
Spiritomb recovers HP.
Turn 8
Pikachu uses Substitute.
Spiritomb uses Dark Pulse and breaks the substitute.
Spiritomb recovers HP.
Turn 9
Spiritomb uses Protect.
Pikachu uses Substitute.
Spiritomb recovers HP.
Turn 10
Pikachu uses Thunderbolt; it's a critical hit.
Spiritomb faints.
Turn 11
Smeargle is sent out.
Smeargle uses Fake Out. It fails to break the substitute.
Pikachu uses Thunderbolt. Smeargle hangs on with Focus Sash.
Turn 12
Smeargle uses Detect.
Pikachu uses Thunderbolt, but Smeargle protects itself.
Turn 13
Opponent gives up.
If they hadn't given up, I'd have KOed Smeargle with Thunderbolt, and also KOed the weakened Snorlax. I managed to get the Battle Pass; most of the Pokémon were IV bred and EV trained. Pikachu is surprisingly good :P