This one sounds hard but in fact it is pretty easy to get.
here is what I did:
Go to the real Events menu and choose the third challenge.
Then go to racing Options and set the race physics to Pro
When you start you have to drive with Maximilian Nagl and win against your two competitors. Since the challenge goes only for one lap it is pretty easy to stay in front.
If you win the race the achievement is yours. :)