Speedball 2 Brutal Deluxe

I actually used the solution from Lucas, but felt it needed a little more explanation for others.

For your first Season i'd recommend holding off spending any money until the players worth 1800/1900 credits become available. There was only a handful in my playthrough from Division 4 to Division 1. I think I picked up 1 in my first Season, and went on to JUST win the 4th Division at the first time of asking, though if you don't gain Promotion in your first Season, don't panic, it merely gives you more time to save more credits and build your team up.

I'd recommend only buying those players worth 1800/1900 credits, as they are the best players available. I had about 4 or 5, the rest were upgraded players I started with. You'll easily have enough cash before getting to Division 1 to upgrade pretty much all your team.

When you get to Division 1 you may well suffer a couple of defeats early on. I let the first Season go through, and went for the Achievement in the 2nd Season in the 1st Division. It's quite easy in all honest, if you're losing within the last 5-10 seconds of a match (you judge whether a comeback is possible) press "Start" and "Exit Game". It takes you back to the Main Menu, but DOESN'T Save your game. Instead, when you go back into Manager League Mode you'll be about to play the match you just quit out of. Keep quitting until you win, then move onto the next match, rinse & repeat for the full Season.

I managed to win the League and only had to "Quit" twice, both times against Fatal Justice (who somehow finished bottom). Once you've seen the "Final League Table" it'll show you a graphics of your team being crowned Champions, much like the Promotion graphic, and the Achievement should pop up once you press "A".

Good luck!

Time- About 1 hour (providing you're "Fast-Forwarding" through matches by holding "X")
It can be irritating having to re-start games in the 1st Division but it's worth it for the Achievement.

This is very boring and time consuming, but the easiest out of the 4 game types. Just keep simulating and making sure you win. If your about to lose, just quit out and try again. I lost 5 times in a row sometimes, but you just need to keep trying and you'll eventually get it. Just make sure u keep upgrading your stats and sometimes buying new people to replace your crappy guys.