I'd just like to add to the other solutions.
I was having a ton of trouble getting this and couldn't use two controllers, took too long.
So what I did was start up a race on easy, do nine laps with ten cars. If you stay between 6-8 position the racers usually drive pretty slow and are very predictable, they will follow the same path every lap, just get close enough to draft them.
If you're too close to the front the drivers are quicker and swerve all over the place, and with the last place drivers; well they are just way too slow.