Nevertheless, it set the scene for tonight's clash at Old Trafford.
This may be the FA Cup and, and with a combined total of 21 triumphs, these are the competition's two most successful clubs, but it is a 90-minute microcosm of the battle at the summit of the Premier League, a contest where the flaws and the frailties of the two major contenders can be scrutinised.
If the English season is often described as a marathon, this year's course is very much a case of the survival of the fittest. United and Arsenal have endured a debilitating and disappointing two weeks that, for one, will contain a depressing conclusion.
This is the stage of the season where Ferguson's teams are primed to peak - and when recent Arsenal campaigns have taken a turn for the worse - but both risk regressing.
Injuries are a prime factor. United are without 10 players, Arsenal at least six.
Those chosen could prove to be the last men standing who still command the trust of Arsene Wenger and Ferguson.
Asked if he had sympathy for the Frenchman, Ferguson replied: "I have sympathy for myself."
Indeed, while it is a hypothetical exercise, it is an intriguing question: would a combined 11 of the sidelined defeat either or both of the sides the respective managers select?
Arsenal's absentees include Cesc Fabregas, Theo Walcott, Thomas Vermaelen, Wojciech Szczesny and Alex Song, while Rio Ferdinand heads a list of United casualties.
This has been a time to try the patience of both clubs. Ambitions threaten to go unrealised.
For United, this season, like last, is all about the 19th title, but the FA Cup assumes a greater importance because of back-to-back league defeats.
For Arsenal, it is the need for a trophy of any variety. A harmful spell threatens to become still more damaging: should they exit a third competition inside two weeks, four will become one in their trophy hunt.
The barrier is both physical and psychological. Old Trafford is a place where most of Wenger's charges have known nothing but disappointment; their past six visits have yielded two goals, one draw and five defeats.
It is also a place where United have a daunting record against all comers this season.
Yet when United are bruised and beaten, a ground should not intimidate. Ferguson has a band of specialists for such occasions, men who invariably excel against Arsenal, yet several are unavailable.
Analyse the United careers of Nani, Anderson and Park Ji-sung and each enjoyed some of his highlights against the Gunners. All, however, are missing.
A scything from Jamie Carragher has sidelined Nani. "We've managed to stitch [his leg], which is great news. What we're guarding against, of course, is infection," Ferguson said. "But to give you a date for when he is coming back is very difficult to say."
Without Nani, this squad seems unsuited to Ferguson's normal game plan against Arsenal. Quick, direct breaks tend to be sprung on the flanks, but Ryan Giggs is the only senior winger who is available. In a midfield where harrying is of prime importance, only Darren Fletcher is equipped to oblige.
Arsenal's is as delicate a balancing act. Fatigue and frustration are twin factors, the pain of their Champions League exit compounded by the unusual sense of being beaten at their own game.
The closest they came to a shot of any sort in the Camp Nou earned Robin van Persie a red card. Shorn of some of their blue-chip players, understudies such as Tomas Rosicky or Nicklas Bendtner have to do more.
If quality is missing in the final third, quantity is an issue at the other end. Manuel Almunia is the only fit senior goalkeeper, prompting Wenger to look for an emergency loan.
"We need now an experienced goalkeeper as cover for Almunia," he said. "We have Wojciech out, in my opinion, for six weeks. We have [Lukasz] Fabianski out for the rest of the season."
So, rather than the battle of the best, this may be determined by who can make do and mend.
This is not perfection.
It is the clash of the patched up.