Rather than join the United States of Mexico in adopting a name that won’t make a difference, the easier way for Australia to subvert chants of “USA! USA!” is through appropriate use of Syncopation. As follows:
A US!A US!A US!A US!
This is not to be confused with German “Aus! Aus! Aus! Das Spiel ist Aus!”, for when Germany won the World Cup in 1954.
Really, Quora. My answer needs to be longer. OK, I tried it out on an American friend living here, and she was suitably annoyed. (The A-U-S version, not the Aus! Aus! version.) Does that help?