While the 4-0 defeat against Chelsea was Mourinho’s heaviest ever Premier League loss, it is only the second biggest of his career.

The biggest: Pep Guardiola’s Barcelona side famously demolishing Mourinho’s Real Madrid 5-0 at the Camp Nou in 2010.

It was Mourinho’s first ever El Clasico and Madrid were humiliated at the home of their fiercest rivals.

Jerzy Dudek, a substitute on that night, revealed afterwards that many Madrid players were in tears after the defeat but the former Liverpool goalkeeper also provided a glimpse into Mourinho's "expert" psychology and how he dealt with big defeats in the past.

"5-0, can you believe it? Barcelona won 5-0. It was the pogrom. After the match in the locker room there was total chaos. Some of us were crying, some were quarrelling, some were looking at the floor." Dudek said at the time.

"Then Mourinho came in. He knew how bad it was but he looked at us and said: ‘I know this hurts you. Perhaps for most of you it is the worst loss of your entire career. They are happy now and seem to have won the championship, but have only won one game. This is just the beginning. There is still a long way to get the title.Tomorrow I will give you the day off, but do not stay in your houses. Go with your families, children or friends for a walk around the city. Let people see that you can overcome this. Perhaps people talk about the significance of this defeat, but do not hide behind it. You must show your balls. After this defeat, we must fight for the title’|

We rose after this disaster quicker than anyone expected. I understood for the first time how important psychology was in sport. How much you can gain or lose. And what an expert psychologist Jose Mourinho is."

The defeat at Stamford Bridge yesterday leaves Manchester United in seventh, six points behind leaders Manchester City.

United have won just one of their last six league matches and face arch rivals Manchester City in the EFL Cup at Old Trafford on Wednesday.

Can Mourinho turn it around?