Finally some spare time.
She will try to upback and backdash away every chance she gets. This is to her advantage because even if we catch her, it won't be a CH and that means we can't do big damage. So we will have to squeeze every last point of damage we can.
Learn the Gurren ~> Enma combos, because you will need them if you punish a jumpout from 2B or backdash with Gurren. Use airthrow to keep her grounded, although that will probably not work. But having the threat is still important.
OD should be used just to make sure that she doesn't immediately burst when you land any sort of good CH.
If she has the bad habit of using both Ds in succession, (like 5DD) you can Yukikaze the first D and she will get hit while she is doing the 2nd D.
Use the Shippu shockwave from full screen to punish sword spamming, or make a guess. Either way it will make her tighten up her defense or get hit.
2B and Gurren are important since she will most likely be trying to get out, or blocking high. You will have to constantly punish that.
If she tries to dash under you while you are in the air, use Agito to stop her.
You can punish her 3C with your 3C.
Don't forget you can use OD to stop the timer if it comes to that.