head-to-head vs neck and neck

head-to-head

adj

  • Direct, one-to-one. 

adv

  • Directly, one-to-one. 

  • Facing one another. 

neck and neck

phrase

  • very close in progress, as in a race or contest 

How often have the words head-to-head and neck and neck occurred in a corpus of books? (source: Google Ngram Viewer )