Sam Wallace: How football's most compelling relationship unravelled in public

Ferguson and Keane: They were united by a ferocious need to win, but when the end came there was no fanfare or warmth

Theirs was an alliance that would change the course of Manchester United, that would shape a decade of English football, and it began around the snooker table in Sir Alex Ferguson's Cheshire family home. Roy Keane was a Nottingham Forest player and one day from signing for Blackburn Rovers, Ferguson had just won his club's first league title in 26 years. The United manager considers himself unbeatable on that particular baize. Keane later claimed that he let his prospective new boss win.

In that summer of 1993, Keane was already a young man who knew his own mind but, even after serving under Brian Clough, he was still a little bashful in the presence of the emergent new Godfather of British football. One remark above all stood out for Keane. "Roy, Manchester United are going to dominate the domestic game with or without you," Ferguson told him. "With you we can win in Europe." It was enough for Keane to tell Blackburn's manager, Kenny Dalglish, who threatened to sue him, that he had changed his mind.

Between them they won 16 trophies, Ferguson recommended that Keane be made United's highest-earning player of all-time, stood by him through terrible injury problems and once arrived at Bootle Street police station in Manchester to collect his captain after a night in the cells. In return Keane led Ferguson's finest-ever team, he led United through sheer force of will and on 21 April 1999 he was the most important reason why they beat Juventus to reach the European Cup final despite knowing that he would be suspended for that game.

When that 12-year working relationship finally came to an end yesterday it did so in a manner befitting the temperament of these two men: without ceremony or warmth or even the opportunity for the great community of Old Trafford to bid farewell to their captain. As a player who once said that he would prefer the presentation of the FA Cup to take place in the dressing-room in order to cut out the hassle, Keane may even have preferred it that way. As a tribute to the end of an era it was a sad way to go.

The public version of Ferguson and Keane's relationship has always been watertight, an affirmation of complete faith in one another. After all, for the many differences they have experienced, they have long shared an even greater mutual antipathy for the press. The scope of which is reflected in that through public critiques of the club's occasional failings from both men, two best-selling autobiographies and the occasional threat to leave, they have kept any differences between them private.

It is those kind of qualities that were one of the many aspects of Keane that Ferguson would have admired but neither of these two men would have been sentimental enough to describe their relationship as anything other than a mutually beneficient, winning partnership. For Ferguson there can be no such thing as a friendship with a player. For Keane, a character as unpredictable and volatile as any in English football, there is only the present: that day's training, that day's mood and an enduring belief in his own judgement.

They have come close to parting before, not least in September 2001 when Keane felt that the hunger of the United team had declined irreversibly and, having been sent off after a dispute with Alan Shearer at Newcastle, believed that, at 30, it was time to move on. On that occasion, and only then, Ferguson visited Keane's home to talk his captain into staying. On the brink of leaving, Keane agreed to play in a Champions' League game against Lille and ended up staying put for another four years. "I did it for Alex Ferguson," he later admitted, "he's stood by me through everything."

Their working relationship has been based upon Ferguson's ability to manage a character as difficult as Keane and, it is tempting to think, it took a man with an equally short temper and just as much courage in his own convictions to do that.

There would have been no chance of Ferguson picking an argument with Keane in front of his team-mates, as Mick McCarthy did with such explosive consequences at the 2002 World Cup. Keane's contribution to United was never put at risk by Ferguson allowing a battle of wills to develop between him and his most influential player.

In Keane, Ferguson had a player who was prone to the most severe mood-swings, unschooled in the art of compromise and happy to admit that he did not count a single team-mate as a friend. That United were given 12 years of exemplary service is testament to the pragmatism in Ferguson's approach to management. Keane has been one of the few players that he has always judged, to a certain extent, to be worth indulging.

There was also much in Keane that reminded Ferguson of the old school of football to which he belonged. The tough Irish Football Association training scheme in Dublin where Keane served his apprenticeship when he was attached to the Cobh Ramblers football club was where his character was formed rather than in the modern club academy that produced the rest of the great Nineties United team. The midfielder was more reminiscent of the tough, working-class footballers who loomed so large in the life of the young Ferguson as he built his own career.

Ferguson has shown no other player the level of loyalty, over so many years, that he has afforded to Keane but as the power of his 34-year-old captain waned it was a pact that he no longer had to keep. His decision, and it would ultimately have been Ferguson's alone, not to award Keane an extension to his contract next summer at last reduced the captain to the status of every other player over the years whose usefulness to the United manager has expired. It was a humiliation that Keane would not bear.

By this week the United captain had played his last card in his game of brinkmanship with the board. First he had threatened that this season would be his last at United with an MUTV interview on 29 September that was intended to flush out some kind of offer from the club. By the time he gave his infamous second MUTV interview, which has never been broadcast, a month later Keane would have been resigned to the fact that he would not be offered another deal. His criticism of the club, especially some of its younger players, was judged by the club to be unacceptable.

There has also been a suggestion that Keane had hoped for Ferguson's recommendation that his captain should be his successor as manager. The process of picking the next United manager is one that the 63-year-old has always said should not, and will not, involve him. That Ferguson was also unwilling to support Keane's cause as a manager contributed to the player's decision to make his break from United as quickly as possible.

The criticism that Keane launched in that MUTV interview remains too extreme for the club to permit it to be made public. Those kind of Keane diatribes used to be the standard by which United's young players were judged, now they have become something from which they must be protected. It was that fundamental shift, that Keane spoke for himself rather than for the good of the club, that contributed to a severe decline in his relationship with United.

He is a difficult man but at least he and Ferguson have that in common. It has always been implicit in every one of Keane's contract negotiations with United that he would be prepared to walk away if the terms were not satisfactory and he has held true to that. His abhorrence of any hint that he might have been conned or sold short is a theme that runs through his life. And despite a relationship with Sir Alex Ferguson that has brought United so much, it was that belief to which he showed the greater fidelity yesterday.