english
1
general::
Phrase(s): *one up (on someone) ahead of someone; having an advantage over someone. (*Typically: be ~; get ~.) • Tom is one up on Sally because he got a job and she didn’t. • Yes, it sounds like Tom is one up.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Having an advantage or lead over someone, as in Sara is one up on Jane because she passed algebra in summer school. This expression comes from sports, where it means to be one point ahead of one's opponents. It was transferred to more general use about 1920.
American Heritage Idioms