Just finished a fight vs ragna on ranked match.
EDIT:
Explanation of post.
At least 20 ragna players I fought used the same desperation strategy to attempt to win when one was on low health.
Combos / DD's rather than single moves.
The DD being the easiest to spot, focusing on a 5D rather than ''when can I attack again'' might get you back to hitting him in the face just a few secs faster.