This achievement is won by winning any 3v3 game. This can me done in Social playlist, ranked, Season, or Exhibition.
To make this achievement easier, load up an Exhibition game with these settings:
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. You can also use this method for the 1v1, 2v2, and 4v4 achievements.
Here's a visual reference as to how easy and fast it is to create and finish an Exhibition map for this achievement: