duel vs pitched battle

duel

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

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

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

verb
  • To engage in a battle. 

pitched battle

noun
  • A battle which opposing forces anticipate and commit to fighting; a sustained, intense and confrontational fight. 

  • An intense, rancorous argument or confrontation. 

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