Manchester City manager Guardiola’s illustrious playing career began at 13 when he was signed by Barcelona and overcame homesickness to board at their famous youth academy, La Masia.

His teammates say his technique was superb, obviously, but what stood out was his uncanny ability to anticipate moves and passes and to marshal others while commanding their respect: hallmarks of his management.

As he always did everything the coaches asked, and more, he was dubbed Mr Perfect. It brought him to the attention of the great Johan Cruyff, then Barcelona’s manager, who became his mentor.

Obsessed though he was with football and its strategies (a friend also calls him Mr 32 Minutes – the maximum length of time they can talk, before his mind drifts back to soccer), the young Guardiola agreed, one day, to model some clothes for Spanish fashion designer Antonio Miro.

The assignment took him to Serra Claret, one of the boutiques owned by the family of 18-year-old Cristina Serra, who was being groomed to become a buyer for the firm and later took it over along with her sister. They soon began dating and the elegant couturier began shaping the scruffy lad from Santpedor into the mohair-cardiganed style icon we see today.

When he landed his first managerial job at Barcelona, aged 37, he had thick, curly locks. When he left for Bayern Munich, four years and 14 trophies later, he was bald as a coot, prompting Mourinho to remark cattily: “When you enjoy your job you don’t lose your hair.”

Now in their early 50s, Pep and Cristina have been together for almost 35 years, and besides their first born Maria they have Marius, 20, a sport and exercise undergraduate, and Valentina, 15.

Guardiola often describes his family as his bedrock, saying he would never make an overseas career move unless Cristina agreed to join him.

In his darkest hour in 2001, he was alleged to have used banned performance-enhancing drug nandrolone while playing for the Italian club Brescia and received a suspended seven-month jail sentence. It was his wife who pulled him through. It took Pep six years to prove the accusation false and have the sentence overturned.

Curiously, however, the pair waited 27 years before marrying, in a quiet ceremony attended by a few friends and family members, in 2014. And for all their evident devotion, they are no longer joined at the hip, as they once were.

Four years ago, it was reported that Cristina would live between Manchester and Barcelona, to spend more time running her fashion business, and this week a well-placed source told me this arrangement continues.

In Barcelona, she stays in the sprawling, £10 million mansion they have bought in the city’s equivalent of Beverly Hills, where neighbours include opera singer Jose Carreras. Cristina’s gravitation back to Catalonia led to speculation that this glorious season might be her husband’s last in Manchester.

However, he has signed a two-year contract extension, his devotion to the city and its people reinforced by their stoical response to the suicide bomb attack on Manchester Arena, which his wife and two daughters – who were attending the Ariana Grande concert that night – narrowly escaped.

He is now the part owner of a Catalan restaurant on trendy King Street, where he often dines, and he says: “I will be a Mancunian for the rest of my life.”

Since he makes time to chat with everyone from the canteen staff upwards at City’s training ground, the love is reciprocated. Yet when he arrived, in 2016, some were unhappy with his all-controlling ways. Not only did he browbeat his players into improving their fitness, he is said to have insisted that every overweight employee should go on a diet, too, because it upset him to look at them.

He also refused to play England international Kalvin Phillips, saying he was too heavy when he returned from the World Cup.

According to French footballer Samir Nasri, who played briefly under Guardiola, the manager – for whom no detail is too small if it might gain an advantage over his opponents – even sought to regulate his players’ sex lives.

To improve their muscle strength and sleep patterns, Nasri claims, he told the City squad they should only make love with their partners before midnight. Guardiola supposedly said that superstar Lionel Messi had improved his physical condition by following this advice during his days at Barcelona.

When he was asked about this at a Press conference, Guardiola gave a typically exasperated, left-field response: “It’s impossible to play good football if you don’t have sex with your partner. It’s not possible!’ he exclaimed.”

Fixing his inquisitor with a trademark sardonic glance, he added: “I never did a ban. They have to do it. The more they do it, they become better players.”

As so often with Guardiola, who has elevated irony to an artform, no one knew whether or not he was jesting. When it comes to the masterstrokes he has planned for tonight, the Italians who stand in his way of the historic Treble will similarly be kept guessing.

Unpredictability is another of his strengths. In recent years he has abolished conventional positions such as centre-forward and full-back, and turned strapping England centre-half John Stones into a deft midfield creator.

Guardiola’s revered mother died, aged 82, from coronavirus in the very early stages of the pandemic. Framed by the mountains she loved, a photograph of her is displayed inside her glass-fronted tomb in Santpedor.

Now 92, his father, who lives in the impressive, orange-brick villa he built, told me this week that the long journey to Istanbul was beyond him, although he had managed to be in Manchester to see City lift the Premier League trophy.

So, he will watch tonight’s match on TV with his sister Maria Carma at his side, trying to keep his blood pressure down.

“He gets so nervous watching Pep’s big matches,” she said, breaking off from scrubbing the doorstep. “I worry about him. I tell him, ‘Stop it Valenti, or you are going to have a collapse!’”

Understatedly proud of his son’s achievements, Guardiola’s father has converted a top-floor room in his villa into a mini-museum displaying his countless honours and prized souvenirs.

During the coming days, he hopes to mount the most precious exhibit of all but, as he told me, for all City’s apparent superiority over Milan, he is taking nothing for granted. “There are so many factors to consider – the referee, injuries, a lucky bounce of the ball – so I just say, let the best man win,” he rasped, adding: “Anything could happen. Football is not like chess.”

Perhaps not – for mere mortals. But for the manager with the sharpest synapses soccer has ever seen, it is exactly like chess. Tonight, we can expect the grandmaster of Manchester to sweep the board. And, as he has always invited his family on to the pitch to celebrate his triumphs with him, we should prepare for a fresh batch of photos from Pep’s increasingly influential daughter Maria.

When she took to the field with the jubilant City squad after they won the Premier League last month, a video of her licking her lips – supposedly in admiration – as handsome Argentinian centre-forward Julian Alvarez walked past her, went viral.

No matter that her gesture was almost certainly misinterpreted, nor that Alvarez was with his girlfriend. In the internet fantasy land she inhabits, impressions are all. Guardiola is proud of Maria, who gained four excellent A-levels from a private college in Manchester, as he is of all his children.

Yet one wonders what the humble bricklayer’s son from the Catalan backwoods must make of the superficial world into which he and his family have been thrust by virtue of his genius.

• Daily Mail report / By David Jones