South Africa got absolutely hammered in the first Test against Australia, losing by 281 runs. Given it was a collective effort of poor batting and superb bowling from Mitchell Johnson, no one can really be spared from the ratings.
If awarding marks with the heart, everyone except Dale Steyn and AB de Villiers would get a big fat zero, but some logic still exists on these pages.
There is no exact science to ratings, and in a massive loss like this, how much a player contributed to help avoid complete embarrassment goes a long way.
The rest is based on whether the player in question actually managed to do anything right. In this annihilation, very few did.