duel vs semifinal

duel

noun
  • Arranged, regular combat between two private persons, often over a matter of honor. 

  • Historically, the wager of battle (judicial combat). 

  • Any battle or struggle between two contending persons, forces, groups, or ideas. 

verb
  • To engage in a battle. 

semifinal

noun
  • A competition that narrows a field of contestants (semifinalists) to a set of finalists, for a subsequent final. 

  • A playoff in the round with only four players or teams left, the stage before the final. 

How often have the words duel and semifinal occurred in a corpus of books? (source: Google Ngram Viewer )