You'll get this achievement by winning 1 tag team duel multiplayer match. I suggest that you boost this achievement along with the Friendly Duelist achievement. People quit out a lot in this game.
To boost:
Create a lobby in Player Match and set it to 3 private slots and 30 second time limit. Invite 3 of your friends and start the match. You can hit RB to change teams. Now, once you get to Rock,Paper,Scissors, you should have the team that will be winning the match choose Rock and the team that will be losing choose Paper. Now, the losing team should wait for the time to run out. The other team will get the win. Every match takes about 2 minutes.