Arsenal's performance against the English Premier League's bottom team was far from their most accomplished under Arsene Wenger. However, the confidence gained from a return to winning ways is just what the doctor ordered for a team that was badly affected by the previous week's slump away to Norwich City.
The hangover from that defeat carried into last Wednesday's UEFA Champions League encounter with Schalke 04. A drab and dire performance followed and resulted in a 2-0 defeat that did as much damage to Arsenal's European ambitions as Norwich had done to their domestic intent.
That made a win on Saturday the most important thing. In truth, the quality of performance didn't need to even enter into it. Three points were vital, simply to get back on track and restore the good feelings in the camp that had been created by a solid start to the season.
A comprehensive victory was unlikely, given Arsenal's fragile confidence and fear of suffering more damage to their season. It's easy to find fault with a narrow home win over struggling opposition, and Arsenal certainly provided plenty of ammunition against QPR, for anyone inclined to look for negatives.
Mikel Arteta's 84th-minute winner was offside and came only after prolonged periods of static movement and aimless possession from the Gunners. There was also the worrying sight of Arsenal yet again almost letting a lead slip, by conceding more than one promising chance to their opponents during the dying stages.
Yet these problems are not terminal, they are merely the manifestation of a team's depleted confidence and resulting fear of making mistakes. That's why the result mattered above all else, because only a win can bring back the swagger and assurance needed to help Arsenal impose their style on opponents.
Those are the qualities Arsenal need in abundance against United. Aside from higher levels of confidence, Arsenal will also need to show the resolve that enabled them to hang on against QPR.
After a series of ugly performances leading to defeats, the belief from surviving a stunted performance with a win could prove crucial in a game when Arsenal can expect to be under intense pressure.
Traveling to Old Trafford low on confidence yielded disastrous results for last season's team, who were fragile after collecting only one point in their first two league games. Playing desperate doesn't suit this particular Gunners' squad either.
Returning to the scene of last season's 8-2 annihilation could well be a defining moment in Arsenal's season. It will be a game in which the quality of performance does count for a lot.
Rebuilding belief and boosting the confidence created by the return of key figures Bacary Sagna and Jack Wilshere is the key ahead of this daunting trip. Saturday's win over QPR is the first and vital building block in that process.