You can do this legit by playing against two AI, with one AI on your team. Just set the difficulty to very easy to make this a breeze.
Or you can put a second controller on the other team so the teams will be: Player 1 and AI vs Player 2 (not controlled by anyone) and AI. Then you can just serve aces against the P2 controller for easy points
A quicker way would be if you have two spare controllers. Set them both on the other team so it would be Player 1 and AI vs Player 2 and Player 3 (both not controlled by anyone). Again, just serve aces to quickly get this achievement