If you are struggling to get this achievement legit, then you have two options:
1. Save before every game, reloading if you do not win/progress.
2. Control multiple teams, preferably ones that have a good chance of winning the World Cup - e.g. Italy, France, Brazil, Germany, Argentina.
Edit: You cannot wait until the final is decided and then take control of both finalists. The achievement will NOT pop. Thanks to
https://www.trueachievements.com/davechambers87.htm.
Please either comment below or send me a Personal Message if you have any comments or improvements.