Ampharos PT vs Gengar

[Blaziken 1111]

Gengar SF is knocked out by damage by an attack. Ampharos PT is in play and it's body stops powers if the pokemon has damage on it. Gengar is knocked out, does ampharos block fainting spell if it gengar had damage before or if it had no damage on it before?

 

[PokePop]

It has damage counters on it, or it wouldn't be being KO'd.
It can't use its Power.