Ian Herbert: Alex Ferguson is right, this is the most important Manchester derby yet

"This was the night when the balance of power swung to Manchester City..." It is the type of pronouncement which has become a part of the modern vocabulary of Manchester derbies and which will be issued once again, seven days from now, if Manchester United lose at the Etihad Stadium. Yet those were the precise words penned 44 years ago by the Daily Mail's Ronald Crowther after one of many occasions which challenges the claim, bolstered by Sir Alex Ferguson on Sunday, that next Monday will deliver the biggest Manchester derby ever staged.

Ferguson generally refrains from superlatives because he doesn't care to give the newspapers the satisfaction, though he couldn't resist this one. "Yes definitely, game on," he said to the notion that the next one will be the most significant encounter he could recall with City. The finale to the 1967-68 English season, which Crowther was writing about, is hardly one that Ferguson would have been following closely. At the time, he was in a Rangers side that was in the throes of being caught up by Celtic, presaging the end of his own unhappy period at Ibrox.

A little of that pain has always stayed with him. But down in Manchester, City and United met under floodlights on 27 March 1968 for what has remained the only clash in which the two have fought for domestic supremacy.

The game doesn't warrant a mention in United's official illustrated history, published by Simon and Schuster two years ago, yet there are many parallels with next Monday, such as how victory – by a 3-1 scoreline, as things turned out – took City level on points with United, the reigning domestic champions, then tying on points with Leeds United at the top. City were the arrivistes, only just promoted from the Second Division in 1966, mid-table the following season, yet displaying signs in the form of Colin Bell, Francis Lee and Mike Summerbee that they might be the upstarts of their day.

It feels like a lifetime ago, now. Two of the '68 game's participants, George Best and Summerbee, were such close friends that they bought a flat together and United's Pat Crerand tells how Best asked him if he could borrow some bedsheets, leading his own wife, Noreen, to provide a beautiful set the Crerands had received as a wedding present. (When Mrs Crerand was annoyed by Best's failure to return them, he told her: "I'm sorry, but they've been well used." She didn't pursue the matter further.) But the intensity of the match – rearranged under lights because the Old Trafford pitch had been waterlogged – was fierce. City conceded in the first minute but goals from Bell, George Heslop and Lee enabled them to pip United to the title by two points.

"A hugely significant moment," says the historian and City specialist Gary James, whose book Manchester The City Years is published in September (www.manchesterfootball.org). "United were the power and City were coming up on the outside."

So how does that decider rank with this one? We are six days away from knowing, because the true significance of a game resides in its outcome. But there were nine games still to go in '68. This time there will be just two – making a minimal safety net for the losers. It will be unbearably tense.

That City have not won the title since 1968 is why, in his own analysis of the world's biggest derby matches, More Than A Game, the journalist Andy Mitten does not even feature the Manchester clashes, deeming United v City to have been too much of a mismatch to qualify, while United v Liverpool does. Mitten, a United supporter and specialist, whose book applied the original Victorian definition of a derby match – "a popular gathering" – was slated by some critics for that omission.

But since 2008, when City entered Abu Dhabi ownership, the Manchester clash has met his criteria. "For years, City didn't keep their part of the deal," Mitten says. "If I was writing my book again, they would certainly be in it. And now, yes, this is the biggest Manchester derby ever. It could only be bigger if the two teams were playing in the European Cup final."

For many, significance is not defined by the potential for silverware. The derby of 24 April, 1974 in which Denis Law relegated his old club United to the Second Division – "like a son turning off his father's life-support machine," as one observer later described it – was of more importance to both clubs than is generally appreciated. City, 14th heading into that game, would have been a solitary point above the drop zone had they lost: it was actually a relegation six-pointer. And while that April fixture that year is always remembered, the grim Maine Road goalless draw a month earlier, with both sides again battling for survival, should not be overlooked, as James points out. Referee Clive Thomas sent off Mike Doyle and Lou Macari, who both refused to leave the field of play, and Thomas took off both sides to calm them down.

There was also the relegation derby of 15 May 1963 – a 1-1 draw at Maine Road that sent City down. In the days when the FA Cup carried far more significance than the league, City's 3-0 semi-final victory over United in 1926 was also monumental.

The significance of an occasion can be retrospectively drawn out, in many ways. When City ran out easy 5-1 winners in the 1989 Maine Road derby, "Fergie Out" chants issued from the United end and Ferguson famously went straight home, got into bed and put a pillow over his head. But it was rumoured at the time that United would not give City the satisfaction of sacking Ferguson on their account.

James observes how Ferguson noted at that time how City had flourished with kids, suggesting that a youth philosophy might have had some roots in a defeat he called "the most embarrassing of my management career" until the 6-1 home loss to City last October eclipsed even that. Ferguson's 1987 Manchester derby programme notes certainly hint at a curiosity with City's youth philosophy. "I admire them for the way they have set about it. It takes time and patience," Ferguson wrote.

Each game takes on its own, deeply personal, significance, though the Abu Dhabi petrodollars have given the current era of derby matches another dimension. The 2010 two-legged Carling Cup semi-final, won 4-3 by United after their defector Carlos Tevez's goals secured a first-leg win, kept what Ferguson then called "the noisy neighbours" at bay. The FA Cup semi-final win of last season stakes a big claim to be the most important derby of all to date, enabling City to cross a Rubicon to silverware and bring down the "35 years" Old Trafford banner.

Now City scent a return to domestic supremacy, too. Crowther's talk of a power shift did not prove prophetic, though money talks in a way which permits far more confidence in a pronouncement like that. Ferguson might have been busy in the riotous spring of '68 but he probably has his historical perspective about right. The next one really is the biggest.

Top ten for tension: Derbies that have lit the Manchester touchpaper

1 - Monday 30 April, 2012. 8pm. Etihad Stadium

So much rests on this one that a draw looks the smart early bet but this could also be the night that nouveau riche City win the jackpot.

2 - 27 March 1968. United 1-3 City

The win that enabled upstarts City to take United's title. Pat Crerand has always put much of that success down to the verve of Joe Mercer's then-assistant, Malcolm Allison.

3 - 27 April 1974. United 0-1 City

Other results that day would have relegated United, with or without that Denis Law back-heel. But that didn't reduce the monumental pre-match anticipation.

4 - 16 April 2011. City 1-0 United

The balance of power is shifting, said Vincent Kompany after this FA Cup semi-final win helped to end City's 35 years without silverware – with due respect to Stoke, it was a semi-final in name only.

5 - 27 Jan 2010. United 3-1 City

United's Carling Cup semi-final second leg win kept Mancini's City – Ferguson's "noisy neighbours" – at bay a little longer, despite Tevez securing a 2-1 first leg win for them.

6 - 21 March 1926. City 3-0 United

City also beat United 6-1 in the league that year but the value attached to the old competition made this, the clubs' first FA Cup semi-final meeting, matter more.

7 - 23 Sept 1989. City 5-1 United

Defeat may have helped United more than City, if suggestions that City's play helped inculcate Ferguson's belief in youth are to be believed. He has hardly looked back.

8 - 7 Nov 1993. City 2-3 United

Ferguson, 2-0 down at half-time before Cantona's two-goal heroics, has always considered this win contributed hugely to United's Double-winning esprit de corps.

9 - 13 March 1974. City 0-0 United

Dour, drab, desperate and almost a riot. Huge pre-match significance as both sides flirted with the relegation that ultimately befell United.

10 - 23 Oct 2011. United 1-6 City

Though too early in the season to be crucial, this was an extraordinary statement of City's intent. Ferguson called it his "worst defeat".

Race for the title

Top two's remaining games

Man Utd 30 Apr Man City (a); 6 May; Swansea (h); 13 May Sunderland (a)

Man City 30 Apr Man Utd (h); 6 May; Newcastle (a); 13 May QPR (h)