How are the human opponents for the fight in Dragon League selected? I've thought they are from the same league as I, but it's not very probable. Usually most of them are far weaker then I - about half of them has dragons level 10, for example, while mine are 15. A few are tough, but in the last leagues one opponent was always extremally tough - with 10 levels above me, very strong dragons. It's impossible those weak guys have beaten him.
Now one opponent is level 50 (mine is 25) and has dragons of level 20, and he is blocking me for weeks that I would need to get my dragons to such high level :( I suspect it's done on purpose to block players from getting gems for free....