The media are always looking for an angle and would have us believe that United vs. City or Liverpool vs. Everton are equally important. They're not.
That's not to say that the involved sets of fans don't eagerly anticipate or wildly celebrate results in either of those fixtures; the bragging results can last for months.
But Sir Alex Ferguson will tell anyone who wants to hear that the matchup with Liverpool is different. Of course, he may be partly doing that to rile his cross City rivals. He still really means it, nevertheless.
Its a cliche to say there are no easy matches in the Premier League, but there aren't. If the luck is running and an illustrious opponent is having an off day, any team can beat any other.
So despite Liverpool having only two points and no wins, nobody will be taking this encounter lightly.
Controversy Must Be Laid to Rest
Of course, there is added spice following the Evra/Suarez ruckus last year. Let's hope that at least is laid to rest with a mutual handshake on Sunday.
There is an ideal opportunity with the aftermath of the Hillsborough papers to end years of vicious and at times disgraceful rivalry between a minority of fans on each side.
Some sort of joint presentation and/or minute's silence would go a long way.
There are bitter historic rivalries between some teams across the globe. In the U.K. the sectarian rivalry between some Celtic and Rangers fans has sadly spilled over in the past, with, for example, threats against Neil Lennon.
That has never quite happened between Liverpool and United, although there have been clashes away from the respective grounds throughout history.
For most fans the feelings between the two sides are harmless enough, but that doesn't stop many United supporters literally hating Liverpool and vice versa. You only have to read the rampant posts by either side on articles about these matches in Bleacher Report to get a flavour.
Sir Alex in last week's press conference called for the vicious chants by each set of fans to end before the match takes place. There are many good reasons why, to which the Hillsborough Papers can be added.
What Makes It the Best?
This article about why the supporters hate each other considers possible historical reasons that go back over 100 years to a time when the two cities rivaled each other as commercial centres. That hardly explains why the match is the greatest and most eagerly anticipated, though.
Much more likely as a basis for modern enmity is the historical pre-eminence of each team as the best in England...and Europe.
There can be no denying that for a period of 20 years or so until the late 1980s, Liverpool were the best team in the U.K. and for part of that time the best in Europe, winning the European Cup four times.
While United have won the top European trophy fewer times, they recently passed Liverpool's total number of wins in the top tier of English football. During the 20-year history of the Premier League, they have undoubtedly been the best.
And, of course, we shouldn't forget the period before and after the Munich air crash when Sir Matt Busby built two great sides, one of which went on to be the first English club to win the European Cup.
Great Managers, Great Players
Both clubs have had great Scottish managers: Busby and Ferguson for United; Shankly and Paisley for Liverpool.
Between them, Liverpool (59) and United (60) have won 119 major trophies.
Every club on the planet has its own folk heroes, but United and Liverpool have more than most. There isn't enough space to list them all.
For United, there are Edwards, Charlton, Law, Best, Cantona, Scholes, Giggs, Beckham, Ronaldo and Rooney. And for Liverpool, Callaghan, St John, Smith, Hughes, Keegan, Dalglish, Souness, Rush, Gerrard and Carragher, just to name a few.
It will be interesting to see how this match develops over the next few years.
Liverpool are in an extended phase of rebuilding, so would they rather face United now, hoping to get a morale-boosting win? What would be the effect if United beat them?
For United to lose to both Liverpool clubs in the first five matches of a season when Sir Alex is hellbent on restoring their pre-eminence ahead of their noisy neighbours would be disheartening.
So, as usual, a great deal rests on Sunday's match. Millions will be watching, hoping for an entertaining spectacle, not more nonsense with handshakes or, worse, still disgraceful, animalistic chants and songs about events best laid to rest.
Every Liverpool vs United match is great in anticipation. The atmosphere is never less than electric. There are always side issues, and, of course, there are the memories of great encounters in the past.
The last five encounters have seen each side win two, with one draw. Overall, Liverpool have won 62 of the matches between the two—United, 72—with 51 draws.
In the League the tally is 53-61-44, but at Anfield Liverpool dominate with 38 wins to 22 losses and 19 draws. Liverpool didn't win a home match in the six years to December 2007, but since then they haven't lost one.
This is a tough fixture for United no matter what the Reds' travails are.
In 1977 Liverpool had dreams of the Treble which United went on to complete in 1999. The two teams met in the FA Cup final for the first time, and United shattered the Reds' hopes, 2-1. Six days later Liverpool reversed that defeat in the League Cup final.
There have been epic recoveries, both ending 3-3. In Sir Alex's first year as manager, United came back from 3-1 down, and in 1994, also at Anfield, Liverpool did even better, from 3-0 down.
Eric Cantona's comeback from suspension for his "kung-fu kick" produced a stirring and emotional 2-2 draw at Old Trafford. Probably the Reds fans' greatest memory is from 2009 when, leading the league, United managed to crumble 4-1 at home. This was their worst home defeat in 17 years, until, of course, City eclipsed it last season.
A Lasting Rivalry
And will the match be as big or significant in five years time, when Scholes, Giggs, Carragher and Gerrard are long gone?
Of course it will.
There will be new heroes, though maybe not with the same longevity as the old ones, but the big ones will be the winning goalscorers—maybe even one of the Spanish keepers?
Who would have thought it, when Busby and Shankly vied for top dog, that Iberian and South American players would feature in this the best, most eagerly anticipated and strongly contested of all the matches in England, between ancient northern rivals?
Away-day fans, today's heroes and great managers will come and go, but the endearing appeal of this particular "North West Derby" will abide for as long as both clubs remain in the top tier.