For the historic clubs there comes a moment when they will not allow themselves to be denied any longer. Liverpool set that process in motion by overcoming Manchester City in the Carling Cup semi-final and now they have removed Manchester United from the FA Cup. The latter success reverberates to a far greater degree.
When Liverpool's followers look back on the week's events they will not be so dull as to debate the details. The surge that is pounding through their minds even now is of the momentum that Kenny Dalglish's side established after the interval here. It was reminiscent of the displays inspired in other days by the beaten manager.
Sir Alex Ferguson is more often associated with the ravenous ambition and limitless endeavour that distinguished Dalglish's men in the second half. The aftermath now sees the United manager at far greater risk of a trophyless campaign. The tie was not distinguished, but the sheer impetus of Liverpool hinted that their old standing need not be out of reach permanently.
Some aspects of what was, in truth, an unkempt match can be mocked, but the victors will think only of their vindication. The extra energy with which they pummelled their opponents late in the match spoke of a team that realised its moment had come. Andy Carroll was the epitome of that.
Once again he did not score but he helped to settle the outcome by acting precisely as he is supposed to do, glancing the long ball from his goalkeeper, Pepe Reina, into the path of another forward, the substitute Dirk Kuyt, to hit the winner while Patrice Evra was stranded out of position.
If United's thoughts were drifting towards a replay by that time, most of the crowd would have been in a similar frame of mind. The hosts, however, borrowed from the Old Trafford repertoire by somehow insisting on victory. At such a moment we recognise the fallibility that the leading clubs hide from us most of the time.
It is a little disconcerting to recognise that Paul Scholes, a retiree until his sudden return to the field, was perhaps the most accomplished performer while his stamina held up. United got 75 minutes of the technique and sheer talent that bolsters a side. On this occasion, that did not suffice.
Liverpool were the inexhaustible force. Dalglish did everything in his power to sustain that intensity. The captain, Steven Gerrard, was even sacrificed after 72 minutes so that Craig Bellamy could bring more verve to bear. The latter, so important in sending the team to that Carling Cup final with his goal against City, would help in sustaining the momentum that proved too much for United.
Dalglish, with his sharp and sardonic humour, would shun any hint that he had been masterful, yet he had made the most of the personnel at his disposal. Liverpool are no longer the sort of club that conquers out of habit. Their last major trophy was the FA Cup, in 2006. It will take much more than a result such as this to prove they have been reinstated among the elite. They stand seventh in the Premier League and a return to the Champions League appears improbable for the time being.
In such a situation, a victory over United is invaluable as an instant means of injecting hope and confidence into players and supporters alike. The context alters with a single result. No Liverpool devotee left the ground wondering what the point was of buying Jordan Henderson or, through gritted teeth, having to steel himself not to admit his dissatisfaction with Carroll in the presence of people who are not fans of the club.
Dalglish will be more relaxed and the unavailability of Luis Suárez, who is serving his ban for racist abuse of Evra in an earlier match, was no hindrance. The grandeur of Liverpool in its heyday will not return by natural right, but a win of this character must help galvanise the club. This was one ground where an FA Cup tie was met not with a yawn, but with a roar of triumph.