The method I used for this achievement is using Scorpion. I mainly used his 'Spear' attack (back,back,x) followed by uppercut (down + y).
If the opponent starts to block this, use Demon Fire (down, back, y). I often use Teleport with him as it attacks the opponent from the opposite side and proves quite effective when timed correctly (down, back, a).
Other than that, simply use block to full effectiveness and time your x-ray attacks right and you should get this achievement in no time.
EDIT: Also use 'Spear' followed by X-Ray attack which will hit 100% of the time if performed correctly.