masterstroke vs pièce de résistance

masterstroke

noun
  • An action which demonstrates great skill or artistry. 

pièce de résistance

noun
  • A masterpiece; the most memorable accomplishment of one’s career or lifetime. 

  • The chief dish at a dinner. 

How often have the words masterstroke and pièce de résistance occurred in a corpus of books? (source: Google Ngram Viewer )