Could you supply a screenshot of your formation, and if possible, a brief-yet-informative description of how healthy and happy your players were before the match began? You may also need to go into more detail for your opponents goalie's statistics, as he may be stronger in his saves than anything else.

Tough luck is all I can say. Maybe you should also try giving your players a win bonus of 2.5K. It's not a lot, really, and it motivates them just enough-- so I believe.