This can be done locally or online.
A match of this game consists of at least 4 rounds (usually 5 or 6), and you start each round with 5 lives. If you make it to the end of a round, you get one point for however many lives you had once you finished the round (example: if I die twice but finish the round, I get three points). The match ends when someone gets 20 points.
If you want this achievement right away, start a local match with an extra controller (you can use guest accounts). Play the game normally with your main controller and ignore your second controller. Your second controller will run out of lives, and you will receive 3-5 points provided you don't make too many mistakes. After you get 20 points, the achievement is yours.
Of course, you can also try to beat your opponents online. In that case, try knocking out your opponents and/or hoping they mess up on their own.