Fans have not always sung his name, as they did in Thursday's Europa League semi-final victory over Basel, but he has always been there, lurking in the dugout and behind the desk in the press-conference room, a charismatic Machiavelli whose record of success was a reminder to his successors that he had done it better.
Even when Carlo Ancelotti won the double in 2009/10, it was with a Mourinho-style 4-3-3 formation and a core of Mourinho players.
Rafa Benitez, whose attitude to the fans who have refused to accept him seems to have passed from denial to irritation to indifference, has continued the process begun by Andre Villas-Boas and Roberto Di Matteo of breaking up the Mourinho core –something almost enforced by age.
Didier Drogba has gone, John Terry is on the periphery, having started only 10 Premier League matches this season, and Frank Lampard, even as he has moved to within one goal of Bobby Tambling's scoring record for the club, has not been offered an extension to a contract that expires at the end of the season.
Even Petr Cech knows that after one bad season he will be replaced by Thibaut Courtois, the Belgian who has excelled on loan at Atletico Madrid.
The shape, meanwhile, has changed to a 4-2-3-1. By accommodating sometimes all three of Oscar, Juan Mata and Eden Hazard, it is far more attacking and rooted in technique than anything Mourinho ever deployed at Chelsea.
It is impossible to know the mind of Roman Abramovich but this is believed to be the sort of football he envisioned his side playing when he bought the club, in 2003.
And yet now, just as the club is beginning to emerge from Mourinho's influence, it seems his return is close.
After Real Madrid's Uefa Champions League defeat to Borussia Dortmund on Tuesday, Mourinho spoke of returning to a club "where people love me", which was interpreted as meaning Chelsea, although the reference was oblique enough to give Mourinho deniability. Certainly, other clubs have expressed an interest, and Chelsea have discussed other names. One of the things that makes Chelsea such a difficult club to read is that everything really depends on the whim of Abramovich.
By Friday, Mourinho was giving what felt like a valedictory press conference in Madrid while insisting his future was undecided. It is possible his statements were a necessary bargaining position in the negotiation of his pay-off. It is believed Chelsea would have to pay around £12 million (Dh68.4m) to secure Mourinho's release. On the plus side, that is 50 per cent less than Chelsea paid Mourinho when he left the club in September 2007; on the down side £30m is an awful lot to pay for changing your mind.
Amid the uncertainty, Benitez was named manager of the month for April. He will not seek to stay at the club when his contract expires in the summer, and the certainty of his departure seems to have left him serene and even faintly amused by the chaos swirling around him.
If he can secure a top-four finish and win the Europa League, he will walk away from the club with his reputation very much enhanced, and today's league game at Old Trafford is the first of two major hurdles, in the space of four days, on the way to the first of those goals.
Beating Tottenham Hotspur on Wednesday may have a more direct bearing on which of the three big London clubs take the final two Champions League qualifying slots, but it would be a huge advantage for Benitez to go into that game with an advantage, knowing then that his side would need only a draw to keep their noses in front.
And it is another opportunity for Benitez to wrangle with his old adversary Sir Alex Ferguson. Benitez's Chelsea got the better of Manchester United in the FA Cup this season and, given that Ferguson becomes more hostile as an opposing manager rises, his jibes that Benitez is only looking after his CV feel almost like a compliment.
There could be no surer sign that Benitez has done a good job at Chelsea.
Manchester United v Chelsea match-up information
Nemanja Vidic v Fernando Torres Chelsea striker Torres has a history of success against Vidic, mainly playing for Liverpool. He is hitting some form and will be key to a Chelsea victory.
Previous meetings In 41 Premier League meetings, each side has 13 victories.
Man United (4-4-2) De Gea; Rafael, Vidic, Ferdinand, Evra; Carrick, Cleverley, Nani, Valencia; Rooney, Van Persie. Chelsea (4-5-1) Cech; Azpilicueta, Cahill, Ivanovic, Cole; David Luiz, Ramires, Mata, Oscar, Hazard; Torres
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