Antonym for "endorsement"?

What would be an antonym for endorsement? E.g.

His poor performance and results served as an (anti-endorsement) of his technical method.


disapproval, criticizing or criticism, reprehension. censure disparagement, depreciation, derogation

Merriam-Webster's Dictionary of Synonyms: A Dictionary of Discriminated Synonyms with Antonyms and Analogous and Contrasted Words


Denounce, or denouncement

Webster definition: “to pronounce especially publicly to be blameworthy or evil”

I was about to ask this same question and then the word cane to me.