Sifting through the wreckage of a defeat at Old Trafford that was far more comprehensive than a 1-0 scoreline might suggest, optimism was the order of the day for Arsene Wenger as he declared that ‘I am convinced you will see a different Arsenal at The Emirates’.
If that prophecy from Le Professeur is to come to fruition, then getting Robin van Persie over the groin strain that forced him to miss Wednesday’s Champions League semi-final is paramount, and potentially decisive, for Arsenal’s hopes of reaching a second-ever final.
The Dutchman was sorely missed at Old Trafford as Arsenal produced a limp performance more in keeping with a desperate first half of the season and not the more engaging displays of recent months. It was not a coincidence.
Meanwhile, United, virtually untroubled by the visiting side, looked every inch the reigning European champions and Premier League leaders with a superb display that deserved far more that the slender one-goal advantage they have earned.
Largely bereft of injury, recent problems aside, this has been Van Persie's finest season by far in an Arsenal shirt and the forward has scored 17 goals and claimed 12 assists in 32 games for The Gunners in all competitions.
But with Van Persie restricted to an observer’s role against United, Cesc Fabregas was asked to take up the mantle (or mantelpiece, as Rio Ferdinand would have you believe) of supporting Emmanuel Adebayor - a Steven Gerrard role if you like.
But Fabregas, for all his brilliance, is no Gerrard; the position just isn’t for him. Yes, he has the vision and technique to pull out a killer pass or three but, despite his brace against Middlesbrough, he certainly isn’t a goalscorer of any repute.
The Spaniard is at home, and at his world-class best, in a deeper role and he demonstrated as much on Wednesday night when frequently dropping back, leaving the deeply-disappointing Emmanuel Adebayor isolated and frustrated.
Similarly, Samir Nasri, who was asked to play deeper, seems to lack the bite needed to play alongside Alex Song and, while the realignment of both he and Fabregas worked well against Middlesbrough at The Riverside, United, it hardly needs saying, represent a far greater threat.
With Van Persie back in the starting XI, Fabregas can attempt to dictate the tempo and direction of Arsenal’s play more effectively in a withdrawn role and Nasri can then shift out to the left, enabling Wenger to surely axe Abou Diaby after his sloppy performance on Wednesday.
This is all hypothetical, of course, and even if Van Persie does return then there is every chance that United will score a goal in North London, leaving Arsenal needing a possibly fatal three.
But football is a game of slim margins and, if Arsenal are to progress, it could be that the hard work of the club’s medical department could be every bit as crucial as Manuel Almunia’s string of saves in the first leg.
After being outfought, outpassed and outclassed by a far-superior United side on Wednesday, it looks as though Arsenal, with Andrei Arshavin cup-tied, need their reliant Robin to be in top gear if they are to have any chance of hitting the road to Rome.
The Eduardo enigma
A final thought... what is happening with Eduardo da Silva? Seemingly fit for the United game, the Croatia international was only introduced with ten minutes remaining and even Nicklas Bendtner got on ahead of one of the very few world-class finishers in Arsenal's squad.
We know Eduardo has been struggling with a number of fitness problems after so bravely overcoming that horrendous injury, but he has played only twice since those FA Cup comeback goals against Cardiff and Burnley - coming on after 85 minutes against Roma and 82 minutes against United.
Still to be tested in The Premier League since Martin Taylor's challenge in February 2008, perhaps Saturday's game against Portsmouth is the perfect venue to again test his suitability for the toughest elite league in Europe.
He was expected to start the 4-4 draw with Liverpool and was nowhere to be seen. Let's hope that one of the club's best players is now both physically and mentally ready for a full return to top-level action.