Role of captain in squad is still a mystery.
it's not a mystery.
Captain is cosmetic, a fun part of the game as trying to simulate real football.
As in real football the captain doesn't affect the performance of the team, same here.
Here is an answer from the devs
http://forum.topeleven.com/top-eleve...-captains.html

and the last one, you can beat Mourinho but must have a 8*- 9* team as there is a "hidden" quality.