Helplessness was the hardest part. When Edwin van der Sar reflects on two of the pivotal derbies of his six years in the Manchester United goal, there is a stark difference. Famously unflappable on the field, the Dutchman was rather more nervous in the posh seats.
Rewind five years and then, as now, United crossed Manchester with three games remaining of a Barclays Premier League season. The title challengers were leading until conceding a penalty. It is the sort of scenario that, on Monday, could make a hero of Joe Hart or David de Gea in half of Manchester.
Yet it is less a fictional situation than a piece of history. Then, up stepped Darius Vassell, but Van der Sar blocked the spot kick with his knees. United's path to glory was clear. "For myself, it was great," he said. "That was a save that gave us the two extra points to stay in front of Chelsea."
Fast forward to September 2009. If Monday's is the most momentous Manchester derby ever, that was the greatest, a match of implausible twists and turns that finished 4-3 and was settled in the 97th minute by a United substitute. By then, however, a fraught Van der Sar had fled, feeling his side's chance had gone.
"I was injured and was watching from the directors' box," he revealed. "The moment [Craig] Bellamy scored [to make it 3-3] I sprinted out and got in my car. I put on the radio and heard 'Ryan Giggs to Michael Owen, Michael Owen scores'. It was an amazing feeling."
Perhaps it was the day when Mancunian meetings became more than just parochial affairs. "Five years ago, it was a derby and that was about it," Van der Sar said. "Now you have got so much more at stake." A title, for instance.
Now Manchester City have 87 league goals, to United's 86. In 2007, however, they were famously hapless in front of goal; Vassell was one of many culprits as City failed to score at home in the league after New Year's Day that season. As Van der Sar said: "The quality of the City team that day was not good."
If the transformation from Greater Manchester's poor relations to the world's richest club dates back to Sheikh Mansour's 2008 takeover, it gathered pace with Carlos Tevez's 2009 rebranding from red to blue. "Initially, I was sceptical," Van der Sar, one of many doubters at Old Trafford, said. "But at a certain point you think: 'They are gelling together. That is a good acquisition'. I was a little bit surprised when Carlos went there. Maybe he wanted to make a statement to United."
Two seasons alongside Tevez brought the Dutchman two league titles and two Champions League finals, one successful. It also equipped him with an understanding of the Argentine and enabled him to provide some perspective on one of the campaign's major controversies.
If much of the footballing world united in disapproval and disbelief when Tevez withdrew his labour, refusing to warm up against Bayern Munich and then disappearing back to Argentina, Van der Sar was an exception. Others were outraged, but he was not astonished.
"That is within his character," Van der Sar said. "He is quite an emotional guy - some of the South Americans are - and with Mancini being from Italy, it did not surprise me. I would not have done that, but everyone is different." He is aware of Tevez's capacity to be the catalyst but feels his former colleague could be a factor in the destination of the title, whoever wins it. "Maybe it is lucky for United that he has been missing but it could be that he is coming to bite us in the back," he reasoned. "You never know."
Tevez's 57 City goals include three dispatched past Van der Sar in the 2010 Carling Cup semi-finals. All were in vain, a 90th-minute Wayne Rooney strike taking United to the final at City's expense. It was a season of three dramatic denouements. "We got a lot of late goals against them," Van der Sar. "Paul Scholes scored in the last minute there [in the league]. It was that mentality to keep on going."
If their mentality has been a historic strength of United's, City have acquired ability, as Van der Sar readily acknowledges. "They have gone and got top players from England and abroad," he said. "It has been a steady rise. It looks they have found the right formula. If they don't win it this year, it will be next year."
Yet he detects reasons for optimism in United's future, too. When Van der Sar retired last summer, Sir Alex Ferguson replaced a veteran with a comparative novice, hiring a goalkeeper two decades his junior.
After experiencing teething troubles, David de Gea has started to impress his predecessor. "There are some goals he could have done better with but he is a quick learner and the way that [goalkeeping coach] Eric Steele is working with him, I think he is doing a good job," Van der Sar said. "He has got quick reflexes, he is good with the ball at his feet and the quality of the saves he has made in the last three or four months has helped them get back in the title race."
And should a City player - Mario Balotelli, Sergio Aguero or even Tevez - find himself taking a pivotal penalty against De Gea, the sense of history repeating itself may encourage United. The obstacle in the striker's path will have certain similarities with Vassell's view in 2007. As Van der Sar said: "He looks a bit like me." As United look for an action replay, they have a doppelganger of an old great to protect them.
Follow Richard Jolly on Twitter @RichJolly
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