As any child would have told you, in the days when the education system was not overwhelmed by classes in citizenship, comic-strip Shakespeare and indoor golf, Portugal is our oldest ally. A walk around the Estrela district of the capital, Lisbon, reveals O Hospital Ingles, where English visitors for more than three centuries have come if unwell, and next to it the Cemitério Ingles, where they ended up if the leeches were not feeling peckish.

An English crusader, Gilbert of Hastings, was the city’s first bishop, in 1147, and Catherine of Braganza, queen consort of Charles II, popularised the practice of tea-drinking in Britain, thereby adding three days to every building job since 1662. She also had a role in the invention of marmalade, apparently, without which, no Paddington Bear.

These days, English references permeate the Portuguese language: something done for show is para Ingles ver (for Englishmen to see); a punctual person displays pontualidade Britânica. So we get along, which is nice.

And just as nations develop a certain harmony, so some football clubs forge a special relationship with a foreign city, too. Usually, it is the work of an historic win; that is certainly the case with Liverpool and Istanbul and, before that, Rome.

What Manchester United enjoy with Lisbon, however, is something more. It is as if the city’s River Tagus winds it way through the recent history of the club, from El Beatle, George Best, announcing his arrival to the wider world at Benfica’s Stadium of Light, to Bobby Charlton’s duel with Eusébio at the 1966 World Cup; from the new United, fashioned from the brilliant talents of Cristiano Ronaldo and other products of the academy at Sporting Lisbon, to the catalyst for Sir Alex Ferguson’s final tilt at greatness, a 2-1 defeat by Benfica in this city on December 7, 2005, the shock of which ultimately propelled his team to a ninth Premier League title the next season.

Tonight, United play in Lisbon again as Ferguson begins his fourteenth attempt to be a champion of Europe. In doing so, he mines a further connection, one that, at first glance, has little to do with his club, but on digging deeper is the essence of what is at stake.

On May 25, 1967, at the Estádio Nacional, amid firs and eucalyptus trees on the road from Lisbon to the picturesque town of Cascais, Jock Stein’s Celtic became the first non-Latin club to win the European Cup, defeating Inter Milan 2-1. The impact on Ferguson, who joined Rangers that year, was profound and explains his continued fascination for the tournament, his desire to be defined by it and the pain of his many doomed quests to master it. The Lisbon Lions are the final link in the chain between this sunny city and its football twin, more than one thousand miles away in Britain’s sodden north.

When United were last in Lisbon, their training ground was situated near to the site of Celtic’s victory. Now lightly used, mostly as a training ground by the Portugal national team, Ferguson led a small band of tourists from the club, including a camera crew from the company television network, MUTV, on a pilgrimage. According to his friend Pat Crerand, as the camera filmed Ferguson in the tunnel, he gave a running commentary, wondering aloud what his hero, Stein, would have been thinking as he walked out to face the Italians.

He marvelled at how a team from such a small country could grow to become the champions of Europe. “They should make a film about it,” Ferguson told Crerard. “They made one about that horse, Seabiscuit. They should make one about the Lisbon Lions, too.” Yet the video footage captured that day was not for public consumption. Crerand claims it was a memento for Ferguson alone; a private moment, for the gentle days when Lisbon is a city to be visited, not conquered.

“Like the Dutch, but speeded up,” was Jimmy Johnstone’s evocative description of the way Celtic played that day and it is a style that Ferguson has spent a managerial lifetime in Europe trying to recapture, not least through his preference for lightning-quick, tricky wingers in Johnstone’s mould. Enter Ronaldo, another of United’s Lisbon connections, having arrived at the Academia Sporting in the Tagus estuary town of Alcochete as a schoolboy with the nickname Abelhinha (Little Bee).

“He reminds me of Johnstone,” Ferguson said recently. “Jimmy was exactly the same – he would get kicked all over the place but he just wanted to get up and attack the big bully that had put him on the ground. Courage is a quality that all the great players have, that is why they can paint the canvas any way they want - and he would run straight at them.”

Just as Johnstone learnt his skills playing in the streets of Bothwell, 12 miles south of Glasgow, so Ronaldo’s distinctive, small-stepping style was honed on his home island, Madeira. Crucially, though, on reaching Academia Sporting, those skills were nurtured, not discouraged.

Regarded by Luiz Felipe Scolari, the Portugal coach, as the premier football academy in Europe, there is no surprise that Ferguson, with his love of the boldness of youth, has sought to cement links between Manchester and Lisbon by tying United to the production line at Sporting. Ronaldo and Nani are the first to progress, their distinct individual styles a result of coaching methods that seek to move away from the Identikit nature of the modern professional, all bulging muscles and functional power.

“The main thing we ask is how skilful is this boy with the ball,” Pedro Mil-Homens, the academy director, said, “how fast can he do things, but always with the ball. It is not so important how tall or strong he is at 12 years old. We concentrate on basic ability. I don’t know if you have this in England now, but in Portugal we still have the space in our daily lives that boys can learn to play football in a very free way.”

Ferguson described Sporting as a fantastic club with a great youth policy, yet Ronaldo, the boy Lisbon passed to Manchester, was until recently about the freedom to play and little else. What Ferguson provided was focus. He acknowledged the unique talent of the player, indulged and supported it, all the while directing it to the pinnacle of the European game by demanding greater mental commitment and a discernable end product, beyond gasps at the audacity of his skill.

It is possible to date United’s reclamation of the Premier League title from the dismal night when goals from Geovanni and Beto left them bottom of a group containing the supposed Champions League makeweights Villarreal, Benfica and Lille. Ronaldo, as a former Sporting man appearing as a club player at the Stadium of Light for the first time since leaving Portugal, received constant abuse and responded by losing his way completely.

When he was replaced by Park Ji Sung with 20 minutes remaining, it was to a cacophony of catcalls, which he met with an obscene gesture. Hard to believe that within eight months, Ferguson had sufficiently steeled him to the pressures of his status as United’s match-winner that he could withstand a similar aural assault every game, as the scapegoat for Wayne Rooney’s dismissal during England’s 2006 World Cup quarter-final. Ronaldo’s 23 goals last season gave United a retort to the number scored from midfield by Frank Lampard for Chelsea and the rest built from there.

“You can’t put it down to one player,” Ferguson said yesterday, “but more to the maturity of the team which has developed since then. At the time we had young players who did not have the knowledge that you see today – but even then, I knew there would be an improvement.” Indeed, the team that lost to Benfica on December 7, 2005, and that which as good as clinched the league title away to Manchester City on May 5, 2007 – only 17 months later – was not vastly different.

Ruud van Nistelrooy had moved on; Michael Carrick and Nemanja Vidic had arrived. What Ferguson instilled was urgency. He accelerated the ageing process in players such as Rooney and Ronaldo, making them grow up and assume responsibility, decelerated it in others such as Paul Scholes and Ryan Giggs, making them determined not to bow out harking back to some golden era lost in time. He identified a rock at the back in Vidic, the heir to Jaap Stam, yet also made this group the most technically efficient in the league. And all on the back of a defeat in Lisbon.

Each Champions League season used to bring a search for omens. In 2002, the final was in Glasgow and the storybook was primed for an impossibly dramatic farewell. Ferguson got the farewell and the drama, but in Germany not Glasgow, his team falling to the unlovely Bayer Leverkusen at the semi-final stage.

A year later there was scheduled to be an Old Trafford homecoming, but this time Real Madrid intervened. This year, the caravan moves to Moscow, which is bound to tug the heart strings of Roman Abramovich – except right now, Chelsea are some way short of being the best team in London, let alone Europe.

Maybe this year then, the significant omen is not where the campaign finishes, but where it starts: for United, in a dry city by the sea, an unlikely home from home on the Atlantic.