Every now and again, a must-win game is just that. Or it is for the man in charge, anyway. Fail and the P45 will be readied, the sack race will have its latest winner and there will be a vacancy that sympathising colleagues will nonetheless apply for in their droves.
As the number of dismissals in recent weeks indicates, plenty of managers are losing the must-win games. Therein lies the key to longevity, perhaps, along with crisis management, where the skill is to avoid the perception of crisis. The most famous and celebrated example of a manager prospering in his must-win match is Sir Alex Ferguson's victory at Nottingham Forest in 1990 or, in shorthand, his 'Mark Robins moment'. Invariably cited as a reason to stick with managers, that rationale ignores the fact that sticking with the wrong manager compounds the existing problems. Persisting with the right one, however, can produce 11 league titles and a couple of Champions League wins.
United's denials that they would have dismissed Ferguson 21 years ago are familiar. So, too, is his knack of producing a result when most needed. Think, for instance, of the awful autumn of 2005: United had been hammered 4-1 at Middlesbrough, a loss at Lille made an early exit from the Champions League more likely and MUTV had seen fit to censor a programme in which Roy Keane laid into various substandard team-mates, prompting his sudden exit. Factor in the unknown element of new owners and Ferguson appeared a man in trouble. Jose Mourinho's all-conquering Chelsea were a rare example of visitors arriving at Old Trafford as favourites, but they were duly defeated by a goal from one of United's most maligned players at the time, Darren Fletcher.
Perhaps it is a scenario that suits Ferguson, management's most decorated streetfighter. Feeling under siege fits his habitual me-against-the-world mentality. Another Glaswegian shares some of his qualities. It is no coincidence that David Moyes is the Premier League's third longest-serving manager. He has endured some awful spells in charge of Everton - taking just two points from the last six games of the 2003-04 season, three from the first eight matches of 2005-06 and three from six at the start of the current campaign - but retains the ability to turn things around. Moyes has lost games, but never the dressing room. If a bad run presents a test of temperament, he has rarely panicked. The consequence is that results have come when most needed - think of Everton's New Year revival in 2006 or the victories against Birmingham, Manchester City and Tottenham in the current campaign.
The key is that events never seemed to escalate out of his control. The same can be said for Arsene Wenger: despite his long wait for a trophy, the Arsenal manager has a brand of consistency, with annual top-four finishes and a virtual immunity to cup shocks, that deflects pressure. Others live more dangerously: Rafa Benitez's gift for brinkmanship only seemed to desert him in his final few months at Anfield but, before then, he had a remarkable habit of winning matches when criticism was at its fiercest.
The comparisons come elsewhere. Managers who are unable to reverse a slide can go from respected to rejected in a matter of matches. Luiz Felipe Scolari's Chelsea were runaway league leaders less than three months before his dismissal, an inauspicious parallel for Carlo Ancelotti to consider. Alan Pardew took West Ham to the FA Cup final and the top half of the Premier League one season; midway through the next, after five defeats in six games, he was gone. Juande Ramos won silverware in his first campaign at White Hart Lane, but appeared utterly clueless as the next began with two draws and six defeats in the first eight league games.
It goes to suggest success is precarious, that if some of the many ingredients required, whether confidence, form, fitness or fortune, are missing then a downward spiral can follow. And that means that only the finest can retain a firm grip for an extended period of time. But even they have pivotal matches, ones they dare not lose.
It is a scenario this year's underachievers should recognise. For Roy Hodgson, the defeats to Wolves and Blackburn proved terminal. For Gerard Houllier, a loss to Birmingham in Sunday's Second City derby could be similarly fatal. With expectations on Chelsea managers rather higher, Ancelotti knows most games come into the category of 'must-win'.
And then there is the great enigma. Avram Grant can often appear one game from the sack. Wins, whether against Wigan, Fulham or Birmingham, have come when a setback might have finished him off. Instead, the Israeli limps on, hoping that something, whether a penalty miss from Mauro Boselli or a goalkeeping error from Ben Foster, will be his turning point. His Mark Robins moment.