Sideline Cut: Whatever the truth about the public disagreement between Alex Ferguson and Roy Keane, that the Manchester United emperor and his chief gladiator for many seasons spent the past week on opposite sides of the world does not bode well for the coming season at Old Trafford.

Comparisons have been made between the row at Manchester United's summer camp in Portugal and the notorious days of Saipan, where Keane's World Cup captaincy went up in flames when confronted by the proud Irish manager Mick McCarthy.

Loyalty to Ferguson and perhaps the lessons he learned from that infuriating episode in Irish sport would have prevented Keane from permitting a private disagreement to slide into a common public row. But the memories of Saipan must have come flooding back to the Cork man. And as then, he was probably disappointed if the facilities and the philosophy of the team training camp seemed to fall short of his vision for the work ethic that he, as leader, should be setting for his colleagues in what is a crucial season for Manchester United.

Since joining United as an exciting midfield tearaway, who drew rave notices with Nottingham Forest, Roy Keane has proven himself as arguably the definitive player in the history of the Premiership and a sportsman whose cerebral attributes far outweigh his natural talents. When the combinations of youth, affluence, the alcohol-soaked culture of English football, a tinderbox temper and an uneasiness with the public eye all brought Keane into situations and places he ought to have avoided, Ferguson stood tough by the man he has chosen as his deputy.

It must be assumed that was partly because he admired and liked the Irish man as a person and understood his situation with an empathy that he did not afford other United players who went wayward under his gimlet Scottish eye. But it was commonly noted that the main reason was that Ferguson appreciated that no other player - not at United, not anywhere in Europe - absorbed and then reflected his own desire to win so often and so fiercely.

There was a period in the mid to late 1990s when Ferguson was unquestionably the most canny operator in English football and seemed to gauge the perfect balance between no-nonsense football patriarch and symbol for the godfather for the nouveau riche Premiership and the wildly ambitious Old Trafford boardroom.

The tale of Ferguson personally arriving to "bust" a house party thrown by early 1990s pin-ups Ryan Giggs and Lee Sharpe seemed like the perfect metaphor of how far he was prepared to allow his team indulge their wealth and celebrity. The flighty, smiling winger Sharpe: not so long afterwards, he had left Manchester United and his most recent appearance was on a lurid reality television show, while Giggs, the deeper talent, has settled into the last lap of his career as a United lifer.

When United won the Champions League in 1999, Ferguson was rightly considered untouchable. That incredible, treble-winning season had the flair encapsulated by Giggs's wonder goal against Arsenal in the FA Cup, the heroism expressed by Keane against Juventus and the deathless spirit that enabled them to almost physically force the Champions League final from Bayern Munich in two unbelievable minutes.

The Scot was elevated to the rare legion of celebrated Scottish managers who came to define English football after the second World War, and with the United bank balance soaring and the franchise making great inroads across the Orient and Asia, the millennium ahead glittered with potential.

That is why revelations of a row over something as trivial as a Portuguese training camp between Old Trafford's thickest alliance must fill United followers with dread. Undoubtedly, Ferguson is desperate to recover some of the lost grandeur this year, as another blank season would amplify the whispered accusations that the fiery old Scotsman has gone soft, that he has lost it. It has been stated he wanted to use the Portuguese week merely to build team spirit before the tour of the Far East.

Keane, though, is not interested in building team harmony through grilling steaks and meeting the wives. For him, the only relevant and useful way of bonding is through the common cause of using a football better than any other team.

The idle days of August have always been notorious for football gossip and it could well be that Fleet Street has created a storm in a team-cup. But the fact United have been forced to comment on the stand-off and that Ferguson reacted so testily, cancelling his regular meeting with the English press this week in Beijing, suggests some of the tension is real.

And in comparison to the news emanating from Stamford Bridge, where Roman Ambramovich was this week rumoured to have approved Jose Mourinho's desire to bring Andriy Shevchenko to Chelsea for a staggering £60 million, the United argument sounds like Vauxhall Conference stuff.

Last year, Mourinho was able to smile slyly as Ferguson and Arsene Wenger bickered like long time Lotharios over a love interest who had long since departed with a younger suitor. This summer, the Premiership's first great managerial rivals have had time to ponder the fact that that war does not matter anymore. The argument that Chelsea are simply buying success is already moot. Over the past few weeks, they have deepened their reservoir of talent and Mourinho has admitted that, should his vast squad of expensive, talented players fail to click, he could well be the first casualty.

The ambition, the money, the cheerfully corporate demand for performance are all new to football and they must bewilder traditionalists like Ferguson as much as they do the general public. Equally intimidating is Mourinho's seemingly effortless ability to embrace his players as a friend, as an equal, while maintaining the unquestioned authority that comes with being the boss.

United's close season was defined by the controversial takeover of the club by the Glazer family from Florida, a group with no emotional or sentimental attachment to the club beyond the potential of its brand name. The success of the club in Asia this week cannot have impressed Brian Glazer, part of the travelling circus. Back in 1999, United played in front of 78,000 people in Shanghai (most of whom wore Beckham shirts). Last week in Beijing only 24,000 fans showed up.

Back in 1999, Keane must have felt reasonably confident he would get an opportunity to play in the Champions League final he missed after picking up a second yellow card as he led by example against Juventus. Now that window has all but closed, and as he looks ahead at diminishing chances his only response can be to push himself to the absolute and to demand the same as others.

Others, such as Ruud van Nistelrooy, must prove that they are not yesterday's men. Wayne Rooney and Christian Ronaldo are the shining gems of the current regime, but, although they will surely delight this winter, how brightly depends on the machine behind them. And while Alan Smith is being groomed - somewhat optimistically - as the man who will replace Keane eventually - this season still belongs to the Irish man.

The fact the Irish man and his long-time Scottish adviser know no other way than to go down fighting makes this Premiership season potentially exciting and real. If they begin this season with any semblance of disunion, then they will surely lose sight of their legacy in English football and the point of the season ahead. And that would be unforgivable in two such smart and proven winners.