User blog comment:FairyRaven/Fairy Tail Chapter 453: A Father's Job, Review and Commentary/@comment-25111584-20150919114604/@comment-5268982-20150919115614

I wouldn't say she was all that normal in Tartaros arc :P she outsmarted Franmalth (an artificial life form and one that's supposed to be superior to humans), and then got some OP power-up and defeated one of the 9DG entirely by herself.

Besides, since she wanted to challenge Natsu to a fight despite knowing how strong he must have been, that shows that she must have improved significantly when it comes down to fighting.