The Premier League season was still in its infancy when Jose Mourinho filmed a charity “joke off” with the Liverpool comedian and supporter John Bishop, as part of a Channel 4 telethon for Stand Up To Cancer. Bishop and the Manchester United manager would take it in turns to tell a joke and the first person to laugh lost that round. Yet the funniest moment remains unseen by most. “OK, a wild card,” Mourinho tells Bishop. “When was the last time Liverpool won the league title?” Mourinho can barely finish his sentence he is laughing so hard as Bishop feigns outrage.

A couple of prominent figures at United were recalling the episode this week ahead of Liverpool’s visit to Old Trafford on Sunday afternoon, when a 10th successive victory in all competitions for Mourinho’s side would carry them to within two points of their Merseyside rivals and rekindle hopes of a title charge that had seemed implausible just six weeks ago.

It is easy to forget now that there were plenty of players and staff at United who, with Louis van Gaal nearing the end at Old Trafford, were privately rooting for the appointment of Ryan Giggs over Mourinho. Giggs, many thought, understood United, their core values, ethos and spirit, in a way Mourinho could never do. But those same people who have watched Mourinho gradually reignite United over the course of the past eight months are also the first to admit that they misjudged the Portuguese.

To fully appreciate the liberating effect Mourinho has had at Old Trafford, though, on mood, morale, training and, crucially, the playing style as well as on the wider outlook of a club whose identity had become muddied since Sir Alex Ferguson retired in May 2013, it is necessary first to go back.