How to deal with sister friede

As the title implies, I'm struggling with sister Friede. I've got the first and second phase down, that is fine, what I don't get is how you're supposed to hit her in phase 3. All she does is do a 5 hit combo and after I dodg, I try to hit her but she just dashes away EVERY TIME. I can hit her once or twice every 5 combos. If anyone else struggled with this, please tell me how you went about it.