Full disclaimer..I do believe this achievement is currently glitched (in a positive way).
I grinded out my racer all the way to level 20 which unlocks the Gumpert ApolloS. Then as I went to online multiplayer (cross play enabled) and got in a lobby with one other racer. I picked the Gumpert and began the race.
When we started we went maybe 500 ft and my opponent quit the race which granted me the xp and the win. Then DING, the achievement popped.
1 short 500ft race magically counted for 5.
I know it's not the best 'guide' as I'm sure it will be patched in the future. Good Luck & Happy Grinding.