Putting Damage on Jirachi DX with Metal nrg

[Tadreth]

I have a Medicham Ex active. My opponent has a Jirachi DX on the bench with 50 damage on it and a Metal energy on it. I use Medicham Ex's attack to put 1 damage counter on the Jirachi DX. Would it be knocked out or would the metal energy stop the 1 damage.

 

[PokePop]

Metal energy won't stop "placing damage counters".
It's KO'd.