In order to get this achievement, you will have to win the Online FIFA World Cup with a team rated 2.5 or 3 stars.
In the Main Menu, select "Online FIFA World Cup" and select a 3 star rated team.
For all teams rated 3 stars check "Three Star Group Stage" above.
Again, use the same method as mentioned above.
Quit out of every match until you find a team that you can beat. This time, if you're a skilled player, you can try to go for matches against teams rated 4 to 4.5 stars, although this still can be difficult.
As stated above, the safe way is to just quit out of encounters and wait for a team that's equally strong or weaker than your team.