Gengar. Who brings out first??

[Prize_Card]

An issue came up when I was playing my friend with gengar.. He knocked my active gengar out, then i flipped heads on his power so the attacking pokemon was knocked out too.. who brings out their benched pokemon out first?

 

[PokePop]

The same as if an Attack KO'd both Pokemon.

The player whose turn is going to be next brings up their Active first.
The player who just attacked gets to go second.