Fixed tennis matches

Our world is full of scandal. Right now there's a lot to do about the fixed tennis matches, where top players allowed themselves to lose a game so that others could gain a lot of money.

Well, I suspected that some tennis players are doping themselves, but who could guess they'd also sell out their matches? And who are those concerned???

Djokovic already mentioned he was contacted by someone to sell out a match - to which he said no. I'd believe him, but can you really tell?