Jose Mourinho's decline as a managerial juggernaut is evident, but what exactly is causing the Portuguese's fall from supremacy?

'The Special One' was practically invincible for thirteen years of his managerial career, spanning spells with FC Porto, Chelsea, Inter Milan and Real Madrid, but the past fifteen months have damaged Mourinho's reputation immeasurably.

Mourinho's infamous 'third season syndrome' occurred at Chelsea as the then-champions produced the worst title defence in Premier League history. Mourinho won just four of his sixteen games as Chelsea boss last season before being sacked in December 2015.

Now at Manchester United, a succession of poor results - not least including a scoreless draw with Burnley on Saturday - has dragged United's inconsistent form back to the surface. Mourinho is clearly struggling to overturn the club's poor fortunes and many believe the three-time Premier League champion is losing his magic touch.

Here at Football FanCast, we feel there are five underlying causes behind Mourinho's miraculous decline.

Fear factor from players is missing

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Jose Mourinho's biggest attribute was his ability to manage his players. At Chelsea, Porto and Inter Milan in particular, the players would almost die for the Portuguese.

Since his Premier League success with Chelsea in 2015, reported player fall-outs enabled crucial members of the squad to revolt against the manager. Mourinho was unable to part with the trouble makers and they ultimately cost him his job at Stamford Bridge.

Now, his invincibility looked shattered and players are almost starting to take control over him.

Unwillingness to swallow his pride

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Manchester United's Bastian Schweinsteiger warms up before the game
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If Mourinho does not like you, your career with him is over. However, unlike before, Mourinho needs to call upon individual players as his critics continue to slate him for obvious failings.

Michael Carrick and Bastien Schweinsteiger's careers at Manchester United looks set to end, with Mourinho unwilling to allow the pair a chance in the first-team. If United were winning weekly, then you could understand. But even with the team struggling, he won't swallow his pride and call upon the experienced duo.

Outdated tactics are not working

Jose Mourinho (Chelsea)

Mourinho's career was built upon his innovation and ability to prevent teams at the summit of the league from beating his sides.

Often we witnessed a Mourinho masterclass by playing five defenders and catching opposition on the counterattack. His most infamous victories included Liverpool in April 2014 and United in April 2015.

But those tactics are becoming predictable and outdated, something defeats to Manchester City and Chelsea this season have proved, and he doesn't seem capable of adapting.

Home ground supremacy

Chelsea v Aston Villa - Barclays Premier League

Death, taxes and Mourinho not losing at home. These were three things once guaranteed in life.

In 12 years, Mourinho lost just one home game in the Premier League before Crystal Palace visited Stamford Bridge in August 2015. Since then, Mourinho has lost six times in 14 games at home and the fortresses of yesteryear have all but collapsed.

Once a historic ground, Old Trafford has become a sandcastle in recent months.

Increasing strengthen of opposition teams

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Unlike Mourinho's first stint as Chelsea manager, lower table teams are now capable of beating any side on their day. With the money in the Premier League, such teams are closing the gap between the top and bottom.

Mourinho has spent fortunes trying to recapture the glory years at United, but the team continues to be outdone by "smaller" clubs who have recruited astutely in the transfer market.