Fabio Capello realised he could win this World Cup very early. Really, it could hardly have been any sooner because the spurt of belief he experienced was on his first working public appearance as the man chosen to re-make England as a serious team rather than a collection of catastrophically self-regarding individuals.
What happened was Wayne Rooney. He came on as a substitute at Villa Park in a deadlocked FA Cup third-round tie in 2008, and didn't simply settle the matter – he made it derisory.
Here in Rustenburg tonight Capello, and much of the rest of the world, will get more of an idea about whether he had an insight, one of the most stimulating of his football life, or an illusion, when the 22-year-old Rooney took the game away from Villa as if they had been guilty of a gross impertinence.
If it was the former, England can indeed win the World Cup or – perhaps we should put it a little more conservatively given the sheer volume of misapplied optimism since the nation's only triumph in 1966 – bring the possibility more sharply into focus.
What is certain is that without the Rooney that Capello came to believe in so fervently, and persuaded to transfer all the joy and ferocity of his work on the training field into the serious action when wearing a white rather than a red shirt, England might just as well resign themselves to another World Cup journey consigned to the margins.
Indeed, there might profitably be a national prayer before the start of the game with the United States. It is that the recent return of Rooney's on-field irascibility, particularly his surly behaviour towards the referee in the warm-up game against the Platinum Stars, is evidence of nothing more sinister than the normal and encouraging meanness of a great fighter when he is close to getting into the ring.
Rooney is so extraordinary in modern English football because if he has so much of that fighter's blood, if he operates so often on that knife-edge between supreme achievement and a terrible, dark frustration, he also possesses an utterly natural artistry. He is a street fighter who wields a rapier – and an innate sense of where to be on the field at any given moment.
It means that it is surely not overly harsh on the rest of the England squad to say that if Rooney is less than what we know he can be tonight against the Americans, if he is too easily diverted by the sense that things are not going quite right, quite as quickly as he would like, the cause is just about lost.
The new captain Steven Gerrard did say as much this week when he said his fellow Liverpudlian shared with Lionel Messi the ability to lift up any side. It was a tacit admission, perhaps, that while Gerrard and Frank Lampard, the two giants of the club game, may still have to resolve their incompatibility issues, there is a certainty about Rooney's potential these next few weeks. We saw that in Portugal six years ago when England were transformed by his brilliance in the European Championships, and then subsided with a terrible inevitability when he was injured.
Most dramatically, we saw it in the Stadium of Light in Sunderland against Turkey in a qualifying match for those championships. In his first competitive international, Rooney was more than merely sensational in his confidence, movement and easy control of the ball. What was so overwhelming was his power to influence his much more experienced team-mates. At one point, Turkey, semi-finalists in the 2002 World Cup, were playing with an easy, almost rippling confidence. They were taking on England, probing their weaknesses and growing a little with each inroad.
Yet the teenager stopped them dead. It is even possible, despite all the intervening dramas of his career, to identify the moment when everything changed. He controlled perfectly a descending ball and set off on a run that was thwarted only by desperate defence. Then it was as though England had been connected to the mains. They had been transformed by a single act of towering confidence.
Can we hope for such a signal on the high veldt tonight? If it is the nation's prayer it is also surely Capello's. He, too, has been showing signs of frustration in the last weeks, even months. The John Terry affair was a most wearisome assault on the senses of a man bred in the culture of Italian football, where players are taught early that playing the game professionally is, whatever the level of their gifts, a privilege and, most properly, a vocation. You do not compromise that standing, nor do you distract your team-mates from the central challenge of going about their business with a sense of unity.
Plainly, Capello was disappointed by what he perceived as a critical lack of progress by his most promising of protégés, Theo Walcott, and when Rio Ferdinand was injured a man of less obvious resolve might have acquired more than a hint of resignation. Yet if Capello does still believe, there is no question about the strongest source of his faith: it remains the man he saw produce such withering authority on that wintry day in Birmingham. A little later he declared, "What I see on the training field is fantastic but when playing for England sometimes he isn't the same player. For England it is vital that he is. He is a great player, a most important player."
Most needed in Rustenburg tonight is a Rooney easy in his own importance, his own value, and the suspicion here must be that it is the one we will get when it matters most. The track record is solid enough now. Four years ago, it is true, he left the last World Cup in an incandescent rage but then he was 20 and had operated under the most appalling pressure: he was supposed to perform gloriously for an expectant nation while plainly hobbled by injury.
He wanted it so badly and yet when it came time to deliver against the Portuguese in the quarter-final he was enraged by the frustrations of a failing effort. David Beckham resigned the captaincy and wept. It is encouraging to believe that Rooney merely resolved that he would return, stronger in his body and more secure in his mind.
Certainly it is encouraging to believe that Capello will not want for conviction when he sends out his men tonight, and that Rooney will be given a sense of his value that is more inspiring than oppressive.
No doubt there are similar psychological challenges being faced in all the World Cup camps. Diego Maradona's turbulent life, for once, might be in other hands than his own, and all of Argentina wants to know if the mixed messages he has directed at Lionel Messi will generate a level of performance more in keeping with the standards he has set at Barcelona but has often found elusive in the white and blue shirt of his homeland.
Didier Drogba, hampered by injury, is a man who demands delicate handling at the best of times, but for Sven Goran Eriksson, dismissed by Mexico and no doubt anxious to leave a World Cup without a gnawing sense of lost opportunity, has arguably the toughest responsibility of all in nursing the most potentially devastating of all the sons of Africa in the next few weeks.
Will Fernando Torres produce the touch and the concentrated speed that makes him arguably the world's best striker and provide for Vicente del Bosque winning momentum for a potentially brilliant Spain? Can Kaka animate both himself and Brazil, can the Dutch stars Robin van Persie, Wesley Sneijder and Arjen Robben arrive together at a mood and in the form to make history?
The questions run as wide as the veldt but nowhere do they go more deeply than those now being asked of Rooney.
There is a vision of him that stays vivid despite the passing of the years and the scale of his achievements. It came quite soon after he announced himself at Old Trafford so powerfully with a hat-trick in the Champions League.
He scored two goals of unquenchable brilliance in a league match against Middlesbrough and when he gunned away from the ground in his sports car, two young fans ran behind, weaving precariously through the traffic, catching up with him when he was at a crawl and then chasing again when he roared off. It was reasonable to believe that the boys simply wanted to touch someone who had brought extraordinary colour to their lives.
It is not the least of the pressure resting on Rooney that much of the nation will be hoping for a similar sensation tonight.
There can be no grounds for complaint, however. It is the fate of anyone who announces he might just be good enough to win the World Cup. England expects, mightily, but then who can say he hasn't provided a number of compelling reasons? Not, certainly, Fabio Capello.
Golden Boot Rivals
David Villa (Spain)
Age: 28 Odds: 8-1
Goals: 38 (in 58 games)
Spain's second highest scorer of all time. Adept on either foot and linked to Chelsea and Manchester City before agreeing a £33m transfer to Barcelona prior to this month's finals. Often overshadows his more illustrious colleague Fernando Torres.
Lionel Messi (Argentina)
Age: 22 Odds: 10-1
Diminutive attacker has just enjoyed another superlative season for Barcelona, scoring 47 goals in 53 games. Argentina hope he can take that form into the finals, although he has struggled to replicate his club form on the international stage.
Wayne Rooney (England)
Age: 24 Odds: 10-1
Goals: 25/60 games
Criticised for his inability to control his temper during Monday's warm-up against the Platinum Stars but also displayed his striking skills. Had a fine campaign with Manchester United before injuring his ankle at the end of March.
Robin van Persie (Holland)
Age: 26 Odds: 10-1
Only returned to full fitness at the end of the season after injuring his ankle playing for Holland last November. One of the best left-footers in the game, the Arsenal striker is venomous from distance and a danger at set-pieces.
Luis Fabiano (Brazil)
Age: 29 Odds: 12-1
Underrated powerful striker who has helped Sevilla to two Uefa Cups in five years while attracting the interest of a number of Europe's big clubs. Top scorer for Brazil in last year's Confederations Cup win.
Fernando Torres (Spain)
Age: 26 Odds: 14-1
One of the more elegant forwards but, like Messi, has often struggled to reproduce his club form with the national side. Endured another injury-hit campaign at Liverpool, featuring just 32 times.