Juventus Match-Fixing
The Juventus match-fixing scandal-tainted Italian soccer for a generation. The team has experienced more domestic success than any of their rivals but it emerged that they cheated their way to two titles. Key club figures applied pressure on referees to favor the Turin giants.

The truth emerged and a massive lawsuit began as the scale of this scandal emerged. In the end, the Italian FA relegated Juventus to Serie B as an unprecedented punishment. The club bounced back and became a force again but its owners had no moral compass at all (via Daily Mail).