If you have the right strategy for fighting Axel, your defense really won't matter.
Start the battle, cast reflect to try and lessen the damage from his first attack, and then attack Axel. Sometimes you'll get lucky and land a full combo, but most times he'll break your attack and kick your butt. Regardless, once your life is in the red do not heal; instead, turn to Limit and L1+O him ( Ars Arcanum ) until he pops out of the stage. Mash triangle, attack, L1+O him, and by the time your life runs out your drive will run out too. Go back into Limit form, rinse, and repeat.