It is the comparison that has always irritated one of English football's great superpowers. For 20 years, Manchester United were judged by the standards Liverpool set; invariably, they came up short. For the past two decades, after a swift, stark role reversal, the Merseysiders have been damned by appraisals against the Mancunians.
But football is comparative; otherwise, the league table would have little relevance. And a look of the two clubs' record in the transfer market over the Premier League era indicates why United's superiority is now entrenched.
As neither has really received a huge artificial injection of money, which has transformed first Chelsea and then Manchester City, or gone into financial meltdown, like Leeds - even if Liverpool might have done had Tom Hicks and George Gillett stayed in charge - they remain the most relevant reference points for each other. Arsenal may be the closest comparison, but they pursued a particular business model under the economist Arsene Wenger. So, once again, it is United against Liverpool and while the Old Trafford faithful enjoy the scoreline Giggs 13 Gerrard 0 - the number of league titles the respective icons have won - the dealings provide some indication why.
1) Quantity and quality.
So far this summer, Liverpool have signed four players - Simon Mignolet, Kolo Toure, Luis Alberto and Iago Aspas - who should be involved straight away and United just one, Wilfried Zaha, plus Uruguayan youngster Guillermo Varela. It is not untypical. In the Premier League years, it is rare that United have needed more than three players for immediate use in the first-team squad; not for a decade have they brought in five, when Cristiano Ronaldo, Tim Howard, Kleberson, Eric Djemba-Djemba and David Bellion formed a distinctly mixed class of 2003.
At Anfield, in comparison, and again ignoring futuristic signings, the arrivals designed to be involved early on numbered five in 2004, 2005 and 2010, six in 2000 and 2008 and seven in 1999 and 2011. That is not automatically a deterrent to success - Sami Hyypia, one of the great pieces of business in Liverpool's recent history, was among the septet in 1999 - but it means the budget is divided more ways. It is easier to get one or two signings right than five, six or seven and it has been harder for Liverpool to concentrate all their attention and resources on securing a couple of decisive deals. The summer of 2006, when Michael Carrick was United's only major buy while Liverpool were bringing in Craig Bellamy and Jermaine Pennant, neither anywhere near top of Rafa Benitez's shortlist, plus Dirk Kuyt, is a case in point. United could pay Spurs' £18.6 million asking price for Carrick. The midfielder's cost appeared extortionate at the time but has subsequently shown the merit of securing a premier target. Sir Alex Ferguson, unlike Benitez, did not need to compromise.
2) Longer and longer
Why do United need so few new players? In part, because many of those they have enjoy such long careers at Old Trafford. Besides homegrown players who either spend their entire career - in the case of Ryan Giggs, Paul Scholes and Gary Neville - or a large period of it, as David Beckham, Phil Neville, Nicky Butt, Wes Brown and John O'Shea did, at Old Trafford many signings become fixtures. In time they will make a loss on Rio Ferdinand, Nemanja Vidic and Carrick, just as they did on such fine servants as Roy Keane, Peter Schmeichel, Edwin van der Sar, Denis Irwin and Ole Gunnar Solskjaer, but this is not about net spend. In many respects, continuity is cheaper. If every transfer is a risk, United are gambling less and relying more on the tried and trusted.
Perhaps a comparison with United is unfair; they are the exceptions to the rule in a world where players move around more. Liverpool, too, have had their one-club men, in Steven Gerrard and Jamie Carragher, plus long-serving imports such as Hyypia, Kuyt, Dietmar Hamann and Pepe Reina, but there has been a high turnover of players in other positions. Ultimately, it has made their task harder.
3) Correcting past errors
There is a sense that Liverpool have spent their time, and part of their budget, chasing their tail by trying to remedy past errors. When a club is signing in the same position in successive summers, it can be an indication of failure and, for example, Liverpool bought left-back Paul Konchesky in 2010 and Jose Enrique as his replacement 12 months later. In the centre of midfield, successive managers brought in their own players every year, usually as their predecessors' choices exited: Rafa Benitez signed central midfielder Alberto Aquilani in 2009, Roy Hodgson brought in Christian Poulsen and Raul Meireles in 2010, Kenny Dalglish added Charlie Adam and Jordan Henderson in 2011 and then Brendan Rodgers opted for Joe Allen in 2012; all this, as well, in a department where Lucas Leiva and Gerrard were constants. Others have lasted a season and a half or two years; since 2004, Liverpool have signed and then sold or released 20 senior players whose first-team careers at Anfield have lasted 24 months or less and United just three. One factor is that Liverpool have had more managers but a consequence is a high number of players occupying the same position in quick succession.
4) The big buys
In one respect, there is little to choose between them. United have spent £10 million or more on 21 players, Liverpool on 18. In another, a gulf separates them. While Andy Carroll is the most expensive player either has bought, United have four signings who are more expensive than Liverpool's next costliest recruit. As a general rule, they can spend more and more often. The consequence is that Liverpool's big buys become more significant. They have less margin for error; unfortunately for them, they have erred too often.
Only four - Fernando Torres, Luis Suarez, Javier Mascherano and Xabi Alonso - qualify automatically for the category of successes, though Daniel Sturridge will join them if he can maintain his healthy strike rate. Several - Carroll, Aquilani, Stewart Downing, Robbie Keane, El-Hadji Diouf - have to be deemed failures, even if they are not always entirely to blame. Of the United 21, Juan Sebastian Veron is the most conspicuous underachiever but while some others did not deliver what Ferguson had hoped, there was nonetheless a dividend: the injury-hit Owen Hargreaves, for instance, helped win a Champions League, along with Anderson and Nani; Dimitar Berbatov finished a season as the Premier League's joint-top scorer. The reality, however, is that when United's major buys have underperformed, others have compensated. When their Anfield counterparts have floundered, it has exerted a greater impact.
5) The key summers
There are times when Liverpool have either threatened to close the gap to United or been offered the opportunity to transform their situation and squad. Such spending, unfortunately for them, has tended to backfire. In 1995, they paid a British record £8.5 million for Stan Collymore, a striker Ferguson had previously wanted, but nevertheless saw their points tally drop in each of his two seasons at Anfield.
In 2002, a year after winning five trophies and having finished second, a place above United, Gerard Houllier had a sizeable budget. Infamously, he declined to sign Nicolas Anelka and bought Diouf, Salif Diao and Bruno Cheyrou, mistakes all.
In 2009, after building the best Liverpool side for two decades, Rafa Benitez lost Xabi Alonso and - unlike in the summers where the budget was divided several ways - spent virtually all of his money on the injured Aquilani and Glen Johnson. A swift decline from second to seventh followed.
Finally, in 2011, owners Fenway Sports Group allowed Dalglish to invest. After the January acquisitions of Suarez and Carroll, the summer brought Downing, Henderson, Adam and Sebastian Coates, among others, and Liverpool's worst Premier League campaign followed. On each occasion, with more judicious acquisitions, the narrative of United dominance might have been different.
The spending spree they may regret most, however, is the original one. Carragher once argued that Ferguson did not knock Liverpool off their perch: Graeme Souness did. The change in the balance of power came when the Scot, granted the biggest budget in England, was wasting it on Paul Stewart, Julian Dicks, Nigel Clough, Mark Walters and co.
6) The future
This is perhaps the most depressing part for Liverpool. With a guarantee of Champions League football every year, the commensurate increase in income and the greater revenue generated by the 30,000 extra seats Old Trafford has compared to Anfield, United now enjoy a huge economic advantage, even if some of their profits are siphoned off by the Glazers to repay the debts loaded on the club.
Liverpool's four summer additions suggest they are already competing in a different market to United. Suarez's desire to leave for a club who play in the Champions League is a worrying warning; it brings unwanted echoes of the departures of Torres and Mascherano and while Ronaldo opted to leave United for Real Madrid and Wayne Rooney has flirted with going, fewer players ask to leave Old Trafford.
As Liverpool are playing catch-up - over the last four years they have been 109 points behind United - they need to buy better than their rivals, but with less money and the problem that some transfer targets will neither want to play in the Europa League or to be out of Europe altogether. The alternative is a vicious circle: they sign players who aren't quite good enough, sometimes paying over the odds, and after a year or two have to replace them, that rather than needing the final piece in the jigsaw, they are forever looking for four or five. Some would say they have been spinning in that circle for several years already.