Not anymore!!! I have found a way of killing an opponent with a chain unbreakable combo that takes all the energy from the enemy without retaliation.
Rapidly tap the attack button non-stop and as soon as the first 3 hits connect, quickly turn and face the other way so that the final uppercut or kick is performed in air, then turn back facing the opponent and repeat the process.
Since right after the opponent is hit, he/she takes time to recover and so by the time you turn round to punch again, there will just be enough time to carry on with the chain.
This is best used for the boss. If done right, you can take out a Boss in under 20 seconds with no damage sustained to yourself.