This solution uses Game Settings to make unlocking this achievement easily. Please do not down-vote if you're a FIFA purist and insists that "everything must be done legit".
This is an extremely easy achievement if you abuse the Game Settings prior to starting the game. Pick any team you want to control and play against. Do the usual and go into the match menu.
Once inside, select "Game Settings". Scroll LT/RT until you reach the part that says "CPU Settings". Here, you'd find all the settings (in the form of sliders) that the CPU would be using against you. "Slide" all the useful settings (e.g., passing, shooting, sprint, acceleration, etc.) to ZERO, and set all the not so useful ones (e.g., GK error, pass error, etc.) to 100.
NOTE: If you want, scroll LT/RT to "User Settings" and slide everything to your favor. That's not really necessary though.
Difficulty does not matter for this achievement.
Now, this requires you to come back from a 3-goal deficit to win a game. The achievement description is a bit fuzzy, sounding as if you need to lose 3 goals in the second half before winning. This in untrue. You can go 3-0 down in the first half by scoring three own goals, and then let the first half and 3-0 to your opponents. From the second half, start banging in the goals against the weakened-by-sliders opponents. You should score tons of goals even on a 4-minute half timer.
If you want, set the difficulty to "Legendary" before the game to unlock this achievement:
The Legendary achievement in FIFA 12 worth 60 pointsWin a game vs. the CPU on legendary difficulty against a club of the same or higher star level