It speaks volumes of Arsenal's inconsistency and unpredictability in recent years that their current run of games is considered a litmus test for their credentials this season, despite having already entered the fourth month of the season. We're ten games into the Premier League, Arsenal are five points clear, having defeated third and fourth placed Tottenham and Liverpool...but conversely, they've also been eliminated from the Capital One Cup by Chelsea, and in a tough Champions League group, their progression remains unassured. The picture should be much clearer after tonight.
Borussia Dortmund is round two of a superb three-match bout. If Liverpool were swept aside with relative ease then last year's Champions League finalists and the reigning Premier League champions should pose a far more significant threat, even if the latter have regressed under the new regime of David Moyes.
In themselves Liverpool, Dortmund and Manchester United are an excellent test of a side's capacities but it is the varying approaches between the trio that makes this a fine opportunity to assess Arsenal's strengths. A curious feature of the week is the fact that in all likelihood Arsene Wenger will name an unchanged side across the trio of fixtures. It is part telling of their injury troubles but also more indicative of Wenger's desire to keep a settled side, and it is with ease one can name the likely approach Arsenal will take to all three matches - fielding three playmakers behind Olivier Giroud and working the ball quickly across the face of the penalty area through quick one-twos, supported by crosses from the overlapping full-backs.
The contrast, meanwhile, between Liverpool, Dortmund and United could not be starker. In the case of the former it was a very unorthodox 3-5-2 that Arsenal had to face and the main concern was that Daniel Sturridge and Luis Suarez could isolate the centre-back partnership of Laurent Koscielny and Per Mertesacker in 2v2 situations on the break.
As it eventuated, though, it was Arsenal's dominance in central areas that proved decisive. The fact the three Liverpool centre-backs were marking a lone striker, Giroud, created a surfeit of numbers in deeper positions for Arsenal, allowing the home side to control the tempo of the match, force Liverpool into deep positions with long spells of possession, and therefore made it difficult for them to transfer the ball quickly to their two strikers on the break.
Arsenal, meanwhile, scored from their two areas of obvious numerical advantage. The first goal stemmed from the wide areas when Bacary Sagna advancing forward to provide the cross for the opener, then later, Aaron Ramsey found space on the edge of the penalty area to fire home the game's decisive goal, emphasising Arsenal's areas of superiority.
Now, though, they face two entirely different challenges. Dortmund attack and defend with an intensity that can be utterly overwhelming, their lightning counters having already proved decisive in the reverse fixture between these two sides. In that contest the freedom both sets of full-backs had on the ball in wide areas was remarkably obvious and inevitably chances were frequently created from overloads down the sides - the winning goal, fittingly, stemming from Kevin Grosskreutz's deep cross towards Robert Lewandowski.
Looking further ahead to Arsenal's upcoming Premier League fixture against Manchester United and the pattern continues. David Moyes's insistence on wing play was long obvious in his eleven year spell at Everton and last night's draw with Real Sociedad showed how Shinji Kagawa's drifts inside can open up room on the outside for the attacking runs of Patrice Evra, who repeatedly drove past the lax tracking of former Arsenal winger Carlos Vela.
Moyes often takes a conservative approach to big games and he will likely select a more solid, defensive player ahead of Evra for Sunday's clash but even then the Frenchman's attacking play remains obvious. He is United's most frequent source of chances with his stream of crosses from deep positions, an approach obvious in its marked contrast with Liverpool's reliance on their front two: it's difficult to remember a moment when the wing-backs, Jon Flanagan and Aly Cisshko, contributed to attacking moves.
Dortmund, too, play with this sort of attacking ambition but combine it with a ferocity of pressing and speed that will be conspicuously absent from Moyes' pragmatic banks of four that will surely feature in the following match. That physical factor, too, with Dortmund likely to exhaust Arsenal with their high-tempo approach, should not be discounted from the following fixture against United.
That, then, presents Arsenal with three completely separate challenges. They've already proven they can beat an unorthodox 3-5-2 that weighed heavily on counter-attacks through a strike partnership; that much is not particularly surprising. Now, though, they face both a side that will pressure them, and a side that will stand off and sit back. It will be fascinating to see how Wenger's side compete against two contrasting approaches.