Even the best managers make mistakes. Within a mile and a few minutes of each other on Friday morning, Roberto Mancini and Sir Alex Ferguson admitted to it, the unspoken corollary being that to do so again before or during this afternoon's potentially epic derby could be costly in the extreme.
Not in terms of unemployment, Mancini insisted, though he would be unwise to depend on that conclusion. The one consolation of Manchester City's elimination from Europe last week, which will cost them money, prestige and a further drop down the Uefa rankings, is that it removes a significant distraction as they attempt to retain the Premier League title. There are many who believe that failure to do so will lead to a change of manager, though Mancini is not among them.
"We went out of the Champions' League and we made some mistakes and I accept all the criticism," he said. "But I think in two years we did a good job because we won three trophies [including the Community Shield] and for us that is important. We have the chance to win more trophies this year. I think in the last two years not many managers won three trophies and if they should sack me…" The sentence was left unfinished.
Having installed two former Barcelona executives in Txiki Begiristain and Ferran Soriano, City could be said to be paving the way for the most important third member of the previous triumvirate, Pep Guardiola, to be reunited with them this summer. Their presence unquestionably makes it all the more certain that the individualistic Jose Mourinho will not be invited; but Mancini insists that he gets on well with Begiristain and will be working with him on any recruitment of players in January.
"He's been here a few weeks now," said Mancini. "He's a good guy and he knows the market very well and we have the same ideas about football. Him, me and Guardiola. I'm joking!"
It is more than 20 years since Ferguson had any cause to use the word "sack" with reference to himself. He was also prepared ahead of today's summit meeting to admit to fallibility, however, in discussing Manchester United's team selection and approach to what became the most decisive fixture of last season's campaign. United went into it three points ahead of their neighbours, just like today, adopted an uncharacteristically negative stance and were punished with deserved defeat.
"I think there was a caution to it, we should have maybe played [Danny] Welbeck," Ferguson said. "But our record in big games with Ji-Sung Park was important. All the big games we always played him and he was always brilliant. But he never quite filled the role in that game." The result was that Wayne Rooney, played as a lone striker, became isolated and United managed barely an attempt on goal all match.
Viewers watching in some 200 countries today will hope the lesson was learnt and that a more compellingly open contest results. Yaya Touré's return in midfield reinstates a weapon City badly lacked in Dortmund last Tuesday and, if David Silva is fit enough, eight big attackers will be available to the two managers.
Ferguson hinted he could pick three of his, for with Antonio Valencia and Nani missing, he needs one of them out wide. "Looking at who I can play in the wide position might be a problem. But with Robin van Persie up front and Chicharito [Hernandez], we've got Welbeck who could play wide, that's a definite option. Maybe Chicharito too. I'm not short of players, I've got a good squad, I'll maybe go for experience and try to work around that."
Come in Paul Scholes, then, the midfielder having appeared against Cluj in midweek only because Tom Cleverley went off injured. Most of the others left out in midweek can expect to return, Ferguson already having demanded that his senior players step up to the plate to improve one of the worst defensive records of his long tenure.
Goalkeeper is an interesting selection too, the hint being that Anders Lindegaard, the older man, has done enough in his recent appearances to keep out David de Gea.
Neutrals around the world would just like to see both him and City's Joe Hart given plenty of work this afternoon.
Fergie's derby landmarks
His first 10 January 1987: United 1 City 0 (FA Cup third round)
Appointed two months earlier, Alex Ferguson was given his first shot at City in the FA Cup, which was won by Norman Whiteside's goal. He won his first League derby 2-0, again at home, two months later, pushing City closer to relegation; they came 21st.
His worst 23 October 2011: United 1 City 6 (Premier League)
"It's the worst result in my history, ever. Even as a player I don't think I ever lost 6-1," Ferguson lamented after a staggering Sunday. City ran in three late goals on the counterattack after Jonny Evans was sent off.
His best 10 November 1994: United 5 City 0 (Premier League)
Still Ferguson's biggest win in his 45 derbies, in front of a modest crowd of under 44,000. Brian Horton was the latest City manager trying his luck but Andrei Kanchelskis scored a hat-trick and Cantona turned it on.
His record P45 W25 D10 L10