I get quite annoyed when i keep seeing these threads.

The outcome of a match in Top11 can be influenced by a variety of parameters. You're players quality is one of them, along with how rested they are, there mental condition, winning bonuses, team formation and tactics, winning streaks, and some sheer luck. We don't know for sure, but perhaps being new on a team can have an effect, or playing in a different formation (such as in the 3 different MC posts). So it is not as simple as buying higher level players - very much like, well, actual football.
So stop being so surprised, play the game, and figure out what makes it work for your team.