There is an age-old saying in football: never go back. Manchester United have learned that lesson the hard way on multiple occasions in recent times.
Paul Pogba, having emerged as a talented youngster, left for nothing to join Juventus in 2012 only to return for a world-record fee four years later. The Serie A giants would laugh to the bank over the summer when they signed the Frenchman - on a free - for a second time.
Cristiano Ronaldo’s departure on Tuesday was even more painful for supporters. Unlike Pogba, the Portuguese superstar had cemented his status as a club legend during his first spell at Old Trafford.
