#4 Sir Alex Ferguson letting Paul Pogba leave
Although the greatest manager in the Premier League era himself admitted his biggest mistake to be his decision to retire in 2001, that error does not make its place here as his revival and the coming years cemented his legacy as one of the greatest ever.
Easily the biggest mistake of the Scot’s brilliant career would be letting Paul Pogba leave prematurely. Sir Alex Ferguson risked a FIFA investigation to bring the youngster to Old Trafford in 2009, and he performed brilliantly with the youth team. However, a lack of opportunities with the senior team and growing frustration at his stunted growth at the club made the player eventually part ways.
Pogba left the club for £800,000, and United recently signed him back for £89 million, so the mistake turned out to be very costly. Pogba has gone on record to say that SAF was the primary reason for him leaving, and since breaking it at Juventus the midfielder turned out to be the powerhouse that the Manchester outfit had lacked for a long time.
Even though the Scot might not admit it, letting such a player leave was probably his biggest mistake ever.