DiRT Rally 2.0

You can do this in a Custom Championship that has only one Event and that Event only one Stage.

After selecting the location of the Event, where you can pick your favorite, you'll need to set the Event Settings. On the Surface Degradation Settings, select "Full". Pick the Vehicle Class you want and press confirm.

Pick a short stage, any one will do. Without adding another Stage, select Confirm. You'll notice that to the right of that "Confirm" button, Track Degradation reads "Full".

Without adding another Event, press and select Championship Settings. Reduce the AI Performance all the way down to 1 (Very Easy). You can run with Hardcore Damage set to "On", but it's harder. Select "Apply" when done.

Start the championship and win the stage. The achievement will pop after you select Continue and go to the podium cutscene.

EDIT: According to Jemdalade, you can make sure it's not glitched by doing the following: I managed to get it to work by doing a custom event, one stage and when you get the option of choosing surface degradation, just cycle through them, then go back to full degradation. Cycling through the options seems to unglitch it.