  Before the Fedal era, and especially during the Sampras/Agassi era, clay was an afterthought. It was Nadal's ability to break out of the clay court specialist mold, and Federer's ability to succeed on clay that has raised clay's profile, at least since the 00s (when I started following tennis).  Champions always secretly believe they are the best, you have to, it's part of the mental makeup.  Sampras in his prime said he believed he was "Unbeatable", this is necessary to be great. Without believieng that you may as well throw in the towel before the match.  