User blog comment:IamJakuhoRaikoben/Chapter 447: Escape Battle, Review./@comment-1153699-20150803144544/@comment-7418318-20150810071900

Granted, Ivan was maintaining a pretty large-scale and intricate illusion while he fought Laxus, but then it was five against one and Laxus seemed to dispatch the whole bunch quite casually. Thus I doubt Ivan was anywhere near Natsu's GMG level (at the time anyway).