In order to get this achievement, you will have to win the Online FIFA World Cup with a team rated 1 star or lower.
In the Main Menu, select "Online Fifaworldcup" and select a 1-star rated team.
For all teams rated with 1 star check "Single Star Group Stage" above.
Even with a lot of skill this will prove to be a near-impossible feat, since being the better player doesn't win you games; there are still other factors that play into this, such as connection, luck, etc. There is a way however, to slightly improve your chances of winning.
Simply quit out at the beginning of each encounter (in the team/jersey screen BEFORE the game starts) if your opponent is too strong for your team (3 stars or higher).
From my experience, there is a chance you will get matched up with people playing with weak teams, too, so if you have enough patience, just quit out of every encounter until you find someone you're positive you can beat.
In total, you'll have to win 7 matches.
- Group Stage (3 matches)
- Round of 16
- Quarter Finals
- Semi Finals