This is earned by scoring a reverse goal during a game of any type. This can be rather tricky and take just the right set up to pull off in an online game. You have to score a goal by reversing into the ball with the back end of your vehicle. If you're struggling to obtain this online, you can use the exhibition method below. Just don't forget to reverse.
If you want to speed up the process, load up an Exhibition game with these settings:
Arena/Map: Any
Team Size: 1v1
Bot Difficulty: No Bots
Mutator Settings: Max Goal = 1
Now you can pick any team you want (it will only be you) and simply make a goal which will end the match immediately and count towards a win.
Here's a visual reference as to how easy and fast it is to create and finish an Exhibition map for this achievement: