User blog comment:IamJakuhoRaikoben/Sorcerer Magazine, Issue 45: September 2015/@comment-25111584-20151003185436/@comment-153.91.238.254-20151004070611

First off that was before the timeskip and second of all what the hell does Erza being an S class mage got to do with anything. S class mage is nothing but a title and doesn't dictate a characters strength or superiority over another character seeing how Gajeel was an s class mage but was still beaten by Natsu.