Ok, here is how to beat him. When the electric lines appear above his head, counter. After you have countered and DS has stopped his attack, you go on the offensive and attack. Here is the key though, do not move the joystick, only use the attack button. Common sense, in most game play, tells you to move in close for the attack. If you do this on DS, you will score some attack points, however, at some point he will counterattack with an indefensible move, i.e. no prompt to counter. Do the opposite of what you normally would. After the original counter, attack use only the attack button, nothing fancy, and you can attack DS up to three times. Then when DS goes on the attack again, during your offensive moves, you will always be given a counter prompt to defend against. Time those correctly and it is relatively simple to beat him. Took me some time to figure it out.