And I don't mean utilizing the challenge system. I mean in the days prior to the challenge system or on a court at a pro tournament that did not have the electronic challenge system installed. I have been watching tennis now for over 20 years and I can't recall ever seeing a pro player successfully argue with a chair umpire and get a line call overruled. Usually, at least from what I have seen, if the chair umpire overrules a call it is on his/her own and they do it right away before a player says anything. In that case, the other player may argue but I have never seen an umpire then go back and say the original call should stand. I certainly do no recall ever seeing McEnroe successfully argue a line call he thought was wrong. The reason for my question is that I believe it appears that it is a complete waste of time and a player's breath to argue because the umpires never change the calls? Has anyone ever seen an umpire overrule a call after a player argues? Why do players even bother arguing in that case?