My only comment after further reflection is that far too much advantage is given to teams that field less-than-5 player teams in league and/or cup matches. The simple fact is that if you elect to do this (or forget to set your defaults properly) then your fifth player should be Atrocious in all stats, and you should get a penalty - especially in the second half - for lack of rest.
For an incomplete squad to be able to take full advantage of all bonuses (CT, enthusiasm, HCA, etc) without suffering negatives, and for an incomplete squad to be able to get a 'lucky fan' with any skill whatsoever, degrades the quality of this game engine
I think, as with a lot of (discussions/arguments) threads here, both sides are correct.
You are right, maybe the game engine should penalize more heavily for something as realistic as playing with a substandard team.
However, the other guys are also correct in that, the game engine is as the game engine is. We all play under the same engine and therefore, irreverent of how any of us feel or think it should be different, it is what it is, and we need to learn how to take advantage of it's strengths and weaknesses (they may not be humanly realistic)
You clearly did not use the most effective strategy (within the perimeters of this game engine) to beat your opponent on this occasion, lesson learned (I have learned a million of them in my short time here).
The fact that you have turned to the forums to get an understanding of the situation is a great sign for the future of your team. Continue to learn the perimeters of the game engine and how to exploit them in your favor and you will climb very fast.
Just think of the game engine as your limitations (what you know works) as well as the variables (what you haven't learned yet) and not like most people who think it should be just adjusted and tweaked all the time because they can't learn to make the most of what they do have. That;s the beauty of the game, five minutes to play, almost forever to master. Best sort of game really!