What is "to have at vantage"

Vantage \Van"tage\ (v[.a]n"t[asl]j; 48), n. [Aphetic form of OE. avantage, fr. F. avantage. See Advantage.]

1. superior or more favorable situation or opportunity; gain; profit; advantage. [R.]

   O happy vantage of a kneeling knee!
   --Shak.

2. (Lawn Tennis) The first point after deuce.

   Note: When the server wins this point, it is called vantage in; when the receiver, or striker out, wins, it is called vantage out.

   To have at vantage, to have the advantage of; to be in a more favorable condition than. ``He had them at vantage, being tired and harassed with a long march.''
   --Bacon.

   Vantage ground, superiority of state or place; the place or condition which gives one an advantage over another. ``The vantage ground of truth.
   --Bacon.

   It is these things that give him his actual standing, and it is from this vantage ground that he looks around him.
   --I. Taylor.