6. Hiring Andre Villas-Boas
It’s not the decision per-se, but the lack of research behind it. At the time AVB was one of the most exciting young coaches in Europe and had certainly earned his move to a bigger club after leading Porto to more success on the European stage. Drawing inevitable parallels to Jose Mourinho, the younger manager struggled to live up to the Special One and made the £14m that Abramovic shelled out to bring him to the club looking like a waste of money. However, AVB came closer to resembling Brian Clough during his time at Leeds and it cost Chelsea a further £20m to get rid. That’s a lot of money for a failed experiment.