hi to obtain this achievement it's easy :
Main menu - Solo - Championship - Official Championship - 450
Choose Ryan Dugey and on the settings put " Very Easy ".
Win few races to be 1st in the ranking after that before you start a race press start then choose the option " Give up the race ".
Keep an eye on the ranking where you see your position in general you have different rankings the 1st when you finish a race you have +25 if you are 1st and after you will have on your screen another where you will see your position in the championship with your all points.
Keep an eye on the ranking where you see all your points, if you are 1st with 20 pts + continue to " give up the race " until the last race otherwise if you are too close of the second play the races and finish 1st to have some points of advance
The last race is Las Vegas do the last race and you will win the achievement after.