The 18th anniversary Saturday of Sir Alex Ferguson's Manchester United career requires no more significant reminder that every great reign depends on perpetual conquest than the unforgiving tribal rivalry of a derby match against Manchester City.
The 18th anniversary Saturday of Sir Alex Ferguson's Manchester United career requires no more significant reminder that every great reign depends on perpetual conquest than the unforgiving tribal rivalry of a derby match against Manchester City.
It has been in these kind of contests that he has shaped his formidable reputation, but last Friday Ferguson explained how he will decide when it is time to step off the stage.
For the City supporters who visited Old Trafford Sunday, with their last memory of a victory in the other half of Manchester a hazy 30 years old, you suspect the departure of Ferguson cannot come soon enough.
But for the 62-year-old himself, the decision to leave Old Trafford will not be based upon a second European Cup or a ninth Premiership title, but the state of his health as he heads towards his 63rd birthday next month.
Unlike the many other aspects of Ferguson that can be relied upon in the course of the football season, the one thing he admitted Friday that no 62-year-old could be "guaranteed" was his health.
Ferguson took great exception to the leaking of the news last April that he had been fitted with a pacemaker and, through his work, has sought to demonstrate ever since that, 18 years on, he is still not prepared to compromise.
Feeling good
"When you get to my age you really are dependent on your health and I feel good," he said. "I feel fit and fresh but you are never guaranteed your health when you get to 63. My health and whether I am enjoying it 'will decide' - that's important."
He has a new one-year rolling contract that was signed in January and will allow him to disguise his ultimate departure date. Although it was understood at the time as if he would have preferred a fixed-term deal, this new contract will allow him to leave on his own terms.
The question of Ferguson's legacy to United has never been something that he has been particularly keen to discuss but yesterday he made it quite clear.
Ferguson's reluctance in 2002 to leave Sven-Goran Eriksson, then the appointed heir, a first-team that he had built, not to mention an academy stocked with the best young talent from Salford to the Ivory Coast, was one of the reasons he postponed retirement.
But the United manager has now accepted that he will not be in charge to see the best years of every young player he has signed.
"What I want to know when I do leave is that I've done my best and have not slackened off - in other words, not given someone else the headaches and problems to solve," he said.
"I want to see the development of a lot of the young players here. If they haven't yet reached their peak when they leave that doesn't matter to me. Manchester United come first and everyone else second."
The visit of City will not be the test that it has been at times in Ferguson's career, like the 5-1 defeat in September 1989 that, even when it was referred to yesterday, caused the United manager to place his head on the table in despair.
His team, despite their eight-point deficit to Arsenal, are still in much better health than Kevin Keegan's side who are without six players, including Trevor Sinclair who will miss the rest of the season.
Perhaps more than that, they have recovered from defeat to Portsmouth last Saturday, a game in which, Ferguson reflected, his side missed "18 chances", to eviscerate Sparta Prague in the Champions League on Wednesday.
Not panicking after that defeat was "down to experience" Ferguson said, just another one of those things he had learned from 18 years in charge. "You get the pleasing performance," he added, "and it justifies your approach."