Graphic: Champions League first knockout round

There was something almost mournful about Sir Alex Ferguson on the morning of September 21 last year. He had come to praise José Mourinho, not to bury him, but, 24 hours after the Portuguese had controversially parted company with Chelsea, the Manchester United manager kept his tributes to a minimum, perhaps unsure of his true feelings about a rival he had regarded with degrees of fondness, affection and, just occasionally, disdain.

From the moment that Mourinho swaggered into Ferguson’s life in February 2004, for a Champions League tie in which the young upstart marked Porto’s surprise aggregate victory with a celebratory charge down the Old Trafford touchline, their relationship was an intriguing one. Despite marked differences in age, background, politics and, in particular, their respective football philosophies, they got on well, more likely to exchange text messages and bottles of wine than the kind of barbs that both would aim at the more inoffensive Arsène Wenger.

They had their disagreements, most notably in the final weeks of the 2006-07 season, when Ferguson took exception to Mourinho’s claim that Cristiano Ronaldo had “no education”, but for the most part their relationship was a cordial one, with each man careful not to antagonise the other. So when they renew acquaintances on the touchline at the San Siro on February 24, do not be surprised to see them shake hands warmly, with the Inter Milan coach addressing Ferguson as “boss”, as he often did, showing deference.

It is a fascinating duel. In this era when coaches are projected every bit as prominently as their players, it is perhaps the most mouth-watering confrontation that the Champions League could throw up: Ferguson, who turns 67 on December 31, is a grizzled veteran of the game, Mourinho suave, close-cropped and immaculately dressed; Ferguson an advocate of fly-by-the-seat-of-your-pants football, Mourinho an arch-strategist who has found his natural habitat in Italy, the land of catenaccio; Ferguson the builder of a dynasty at Old Trafford, Mourinho the itinerant whose three-year spell at Chelsea was the longest of his coaching career.

There is another element to all of this. Reports have already surfaced suggesting that Mourinho is being targeted by United as the man to fill the void when Ferguson retires, which is likely to happen either at the end of this season or the one after. In reality, David Gill, the United chief executive, has never had a serious conversation with the club’s owners, the Glazer family, about the succession, but, even if Mourinho seems at odds with the Old Trafford philosophy of free-flowing football, as laid down by Ferguson and the late Sir Matt Busby, the self-anointed “Special One” would merit consideration — particularly if he can win another Champions League this year, knocking out United en route.

United, as holders, will be favourites, but Ferguson will need no reminding of his poor record in head-to-head meetings with Mourinho. Going back to Mourinho’s time at Porto, they have met ten times as opposing managers, with United winning once (though they may lay claim to the 2007 Community Shield match, in which they beat Chelsea on penalties).

Few of those matches were memorable — least of all the 2007 FA Cup Final, in which Didier Drogba scored the only goal for Chelsea in the final minutes of extra time — but that was how Mourinho liked it. When it came to attrition, few teams were better than his Chelsea side, built around the strength of players such as John Terry, Claude Makelele, Michael Essien, Frank Lampard and Drogba.

Mourinho set out to construct his Inter team on similar lines and, with a strong, tight central midfield that usually includes any four from Esteban Cambiasso, Javier Zanetti, Patrick Vieira, Sulley Muntari and Dejan Stankovic, there are parallels with his Chelsea team. Although they lie six points clear of Juventus at the top of Serie A after one defeat in their opening 16 matches, Mourinho would argue that they are not yet at that level. But he gave warning yesterday that they will be much closer when the time comes to face United. Roll on February 24.