José Mourinho fears that there is an error with Adnan Januzaj's birth certificate. "He's not 18, he's 25," the Chelsea manager jests of the prodigy who will carry the fight for Manchester United at Stamford Bridge on Sunday. "He is so mature, so comfortable. A fantastic player. He has great conditions to have a long‑term career at United. I don't know the boy individually, but it looks like he has everything."

Januzaj represents an ideal that Mourinho has come to covet and that, he admits, is among the principal drivers of his second spell at Chelsea. Januzaj, who has shot to prominence this season, is not exactly a home-grown product – United took him from Anderlecht as a 16-year-old in 2011 – but he is a player who has made the transition from academy prospect to first-team regular.

"You can see that since I left [in 2007], Chelsea didn't really have a player coming direct from the academy to the first team," Mourinho says. "John Terry was the last and it was not with me. It was before me."

Terry became an important member of the Chelsea first team from 2000-01 onwards – and if he is a symbol of the old school, ranks-to-riches route, Januzaj is today's twist: a player of diverse heritage who moves freely in a smaller world. Mourinho simply wants a graduate from the Chelsea academy, however late they arrive and however many times they jump in and out of the club on loan. "It's very important," Mourinho says. "It's something I really want to happen."

Chelsea are doing everything they can, from the grassroots to arrangements with clubs such as Vitesse Arnhem and Middlesbrough, where players can develop on loan – although the signing of Nemanja Matic for £21m from Benfica on Wednesday does not look like an example of joined-up thinking. The midfielder was allowed to leave Chelsea three years ago as a makeweight worth £3m in the deal that brought David Luiz to Stamford Bridge from Benfica.

Mourinho talks up the role of the technical director, Michael Emenalo, while he also works closely with the academy manager, Neil Bath, and Eddie Newton, who liaises with the many players who are out on loan.

There are five of them at Vitesse, including Lucas Piazon and Bertrand Traoré, while the highly rated Nathaniel Chalobah has joined Kenneth Omeruo on loan at Middlesbrough, where Aitor Karanka, Mourinho's former assistant at Real Madrid, is the manager.

Tomas Kalas and Lewis Baker have appeared for the Chelsea first team this season, and Mourinho mentions the progress of Nathan Ake. There are hopes for Thorgan Hazard, Eden's younger brother, and Patrick Bamford, who are on loan at Zulte Waregem and Derby County respectively.

"Emenalo is working hard and choosing the right place for the players to go and play, to evolve," Mourinho says. "We watch them every weekend. The information comes to me online immediately, so I can know where Chalobah is, little Hazard, what they do.

"We have contacts with their coaches and their clubs. It's not something you can just click and make happen. It needs time.

"The academy is very well organised and the transitional period [into the first team] is something that the club is having a lot of care with. So, normally, it has to work."

Januzaj is a young man in a hurry, but Mourinho is older and wiser, more patient these days. His management style has changed, he said, as he looks at a broader and long-term project at Chelsea, during which he intends to set a new mark for managerial longevity under Roman Abramovich.

"I have the record … three and a half years," Mourinho says of his first spell in charge. "I have to try and beat the record. I have a four-year contract, so hopefully I will beat the record.

"I reflect a lot about my style of leadership. One thing is where I want to try to get the best results immediately and, for a couple of years, your leadership can be much more confrontational. It is one thing to have a relationship with my players that I know are going to be my players for a couple of years and another thing to educate players with a relationship and with an empathy that I'm sure is going to be for five, six, seven, eight years."

Abramovich is also a different beast. "He is an intelligent person and intelligent persons, even if they are not experts in certain areas, will learn a lot," Mourinho says. "So, in 10 years of experience, working closely with managers and the club, and so on, it is easy for him to add experiences and understand better what he wants."

What everyone wants is a player to emerge and excite like Januzaj.