User blog comment:SethHeartphilia/Whos stronger Erza or Mirajane/@comment-26156772-20150608135226/@comment-26461051-20150612003318

Sure. But Erza has a wider variety of attacks and strategies she can use, and she has better defensive options, too.

Mira's attacks dwarf Erza's, but Erza generally fights smarter... (Read some of my comments below if you want an explanation)