Here is definition of world class i have just invented, i think it's pretty accurate!
You have to imagine ur on Family Fortunes & Vernon Kay has asked 100 people Who Is Best ____ In The World. Ur answer don't have to be top answer, it don't even have to be on board, it just mustn't be one of the dumb answers that makes the audience lols
I.e. If it was Who Is Best Left Back In World, and you was "Ashley Cole", audience might not agree but they would sit quietly on their hands (World Class). If you was "Danny Fox" they would be rolling in aisles, i.e. Not World Class!
hope this helps