Ruling Crustle BCR and Focus Sash

[Machamp The Champion]

If I have a Crustle Active with a Focus Sash attached, and the Crustle is knocked out with full HP, which effect prevents Crustle from being knocked out first? The Focus Sash, or Crustle's ability Sturdy? Depending on which one takes place first, the Focus Sash may or may not stay on Crustle.

If I were to take a guess as to the correct ruling, I would be able to choose which effect takes place first, as I am the owner of the cards and thus choose which order their effects take place.

Thanks in advance!

 

[TheStrictNein]

Yes, as owner of the card you get decide which effect takes place first, only because they occur at exactly the same time.