Ok so after doing my 8 play throughs to get the other 925G i still hadnt entered or won this cup... so my suggestion is to do another play through with Totenham Hotspurs
After skipping the pre-season i had a C.E.F.A. Cup match scheduled on the calendar.
Play the season as normal but make sure that you win every C.E.F.A. Cup match (Click right stick to see match details) then once you get to the end of May you should have made it to the final, win the final and this achievement is yours.
This took me about 1-2hours
Note: Thanks to Van Uden
for the team suggestion.