By long-standing tradition Arsenal supporters celebrate the day each season – St Totteringham's Day – on which it becomes impossible for Tottenham to finish above them in the table. For Manchester United followers even to think about such a thing in relation to their own most local rivals would probably have been considered beneath them – where City have been found for the most of the past three decades, sometimes not even in the same League.
Yet as north London confronts Manchester this afternoon at the Emirates and the Etihad, evidence of changing times will be apparent in more than the names of the venues. Having not finished above Arsenal for 17 years (see graphs right), Spurs travel north sitting in third place, fully 10 points ahead of them. Meanwhile, a similar inversion is threatened in England's third city. How has this come about? Essentially, in the transfer market.
To take the London rivals first, the simple fact is that Harry Redknapp has spent better than Arsène Wenger and the startling one is that in assembling what would be regarded as the two clubs' strongest teams, Tottenham have spent less. When Redknapp succeeded Juande Ramos in October 2008, Spurs were bottom of the table with two points from eight games. Arsenal were fourth, where they stayed until the end of the season, by which time Redknapp had taken Spurs to eighth place and the Carling Cup final.
The gap between the teams was still 21 points, which Tottenham reduced to five the following year as they qualified for the Champions' League and six last season, one place behind Arsenal in each case. Then an eventful close-season centering around key midfielders came to symbolise the two clubs' financial philosophies and offer a hint about how this campaign might pan out. On the day in mid-June that Luka Modric made clear his desire to join Chelsea, the Spurs' chairman Daniel Levy insisted "none of our key players will be sold this summer" and to widespread surprise he was able to stick to his guns.
The start of their season was still disrupted, contributing to heavy defeats by the two Manchester teams in the opening games, but by the end of the transfer window, Spurs had held on to Modric, signed Emmanuel Adebayor on loan, Brad Friedel for nothing and the Footballer of the Year Scott Parker, while showing a profit on transfer dealings of almost £15m into the bargain.
The Modric-Parker partnership of silk and steel in central midfield has worked perfectly, Friedel has taken over as competently as expected from the less predictable Heurelho Gomes and Adebayor has brought goals that were lacking from the strikers last season. In contrast, Arsenal's fears of summertime blues materialised just after the season had started when in the space of nine days Cesc Fabregas finally went home to Barcelona and Samir Nasri made it clear that he would take the Manchester City shilling (or dirham). Having lost a third key midfielder in Jack Wilshere to injury, sold Emmanuel Eboué and not bought any replacements, Wenger was forced into an uncharacteristic spree, securing four players on the deadline day. The fees for Fabregas (£35m) and Nasri (£24m) meant Arsenal were again in profit but as a growing number of more critical supporters regularly note, League tables do not include those figures.
What they do show this morning is that Wenger's team have lost seven games (including the derby at White Hart Lane) to Tottenham's three, scored one fewer goal and conceded 10 more. They have suffered far worse from injuries, with the defence in particular badly affected, but of all the new signings Mikel Arteta has been the only unqualified success.
The most important target now for Arsenal is to catch not Spurs but their other main London rivals Chelsea, who currently hold the critical fourth position that brings a Champions' League place. When Wenger talks of the club's achievements during his 15-and-a-half years, he does not mention having been above Tottenham every single season but points proudly to an unbroken run of 14 successive Champions' League campaigns. That is what is at stake now.
In Manchester the stakes are both more and less parochial, for unless Spurs and Arsenal bring off an unexpected double this afternoon, City's quality and United's experience would appear to remain the defining factors in the championship chase. The sort of experience that United and their manager have built up over the years cannot be bought. Quality can, however, and City have purchased it by the bucket-load. Yet if there is a surprise in comparing the strongest XIs of the two clubs, it is that United's is less than £30m cheaper, so that at £158m that team cost three times as much as Tottenham's and almost two and a half times as much as Arsenal's.
Handing over huge sums for players like Rio Ferdinand, Wayne Rooney and Dimitar Berbatov before City's fairy godfathers arrived, United were always bold spenders, living up to the tradition of a club who have broken the British transfer record more times than any other. The only change in philosophy has been to go in for younger players, and that may cost them in the short-term. They lead City by a vast distance in turnover and the ratio of income to wages and are better placed to deal with Financial Fair Play. But those figures will not influence which club are crowned champions in four months' time.
Manchester City v Spurs is on Sky Sports 1 at 1pm
Danger man: Ferguson wary of the one who got away
Manchester United's manager Sir Alex Ferguson is hoping that Robin van Persie, whom he once considered signing, does not further undermine the champions' attempt to retain their title when United visit Arsenal this afternoon. Ferguson has recalled going to see a young Van Persie play for Feyenoord reserves: "He either got sent off or walked off, I can't remember. We just left it alone at the time but he has turned out to be a fantastic player. We weren't worried about his disciplinary problem, I think Arsenal were closer to the situation than we were at the time."
The Dutch striker has scored 18 goals in 21 League games this season, emerging as the type of outstanding forward who Ferguson says makes a difference; a category into which he also puts Lionel Messi, Cristiano Ronaldo and David Silva for their respective clubs.