Okay, so my tip for this achievement, is to play at midnight, European time, on a week day. As sad, as it may sounds, there's more bad players at this moment, and I can't really explain why.
Try using Manchester City, and play with 1 striker. That striker should be Mario Balotelli. Play with Aguero and Silva on the wings, and Nasri on a CAM/CF position.
With Joe Hart on the goal and Kompany in the defense, you'll have a brick wall behind.
With this team i managed to win 2 cups in a row, with a total score of 19-2 in goals/against.
And as mentioned in other guides, PRESS B INSTEAD OF A ON THE CHAMPION SCREEN. I pressed A first and did'nt get the achievement, but afterwards I won again, and pressed B to obtain this achievement.