face-off vs point of contention

face-off

noun
  • A confrontation or argument between two people or groups 

  • The start of play, when two players try to get control of the puck dropped by the referee 

point of contention

noun
  • A matter that forms the basis of a disagreement, struggle, etc. 

How often have the words face-off and point of contention occurred in a corpus of books? (source: Google Ngram Viewer )