The great homecoming for Fabregas was meant to be Barcelona. Mourinho's coronation as the top coach in Europe was meant to come at Real Madrid.
Instead it could yet be England where these two former Clasico enemies create their masterworks.
It was at Stamford Bridge in his first reign where Mourinho displayed his true tactical acumen, team-building skills and gift for handling stars. Not once in his travels since has anyone accused him of art for art's sake, or of seeing management as an attempt to write a masterpiece.
Fabregas, though, was a signing based on fluidity, panache and spatial awareness as well as toughness of character. He is one of the few in today's top tier capable of running not just his own department but a whole game.
Most top coaches want to construct a side of universally acknowledged brilliance. Arsene Wenger's "Invincibles" and Manchester United's treble-winning side of 1999 cannot be dislodged from history. Though Mourinho has put together many formidable trophy-winning sides, at Porto, Chelsea, Inter Milan and Real Madrid, he, and not his teams, are always the story.
Last season was all about his willingness to go along with the brief he inherited: more ambition, more entertainment. By December he had found his justification for dumping these abstractions. The first time Chelsea conceded three goals in a game it should have been obvious that he would seize his chance to return to the old conservatism.
But he had another trick: constant grumbling about the quality and depth of his squad. He talked like a man who had been asked to conquer Everest in flip-flops.
And he almost pulled it off, until the team he accused of not being up to the job played into his hands by dropping too many points in spring.
The summer brought two of the most impressive and sensible buys - Diego Costa, a finisher and barnstormer, and Fabregas to link midfield and attack.
In goal, Chelsea have pulled off the miracle of finding a keeper capable of relegating Petr Cech to the bench. The return of Thibaut Courtois from his loan spell at Atletico Madrid is a spectacular windfall.
Monday night's win over newly promoted Burnley suggested serendipity all round - a brilliant new goalkeeper, the ideal striker and the perfect midfield orchestrator, who knows the Premier League. Chelsea fans will be rightly protective of their Champions League-winning side and the teams Mourinho assembled to end a 50-year wait for the English title.
But, logically, why should he stop at trophies? Why should he bulldoze a path to the title when he has players who can dance their way there: Eden Hazard, Willian, Andre Schurrle and Fabregas, who could never get around the stardust problem of Xavi and Andres Iniesta at Barcelona?
Because haunting his brain is the belief that football is an exercise in power, not beauty, and that winning is power. But with this new side Mourinho is displaying his highly developed knowledge of how successful teams work. He saw what was missing and went shopping for it.
The next time we call him an anti-football manager we will have to qualify it by saying he bought Cesc Fabregas - a creator, not a destroyer.
The big 3 games
1. Everton v Arsenal, Goodison Park, Sunday 4.30am.
2. Spurs v QPR, White Hart Lane, Monday 12.30am.
3. Manchester City v Liverpool, Etihad Stadium, Tuesday 7am.
