Five months is easily long enough to make nonsense of a supposition made today but it is tempting nonetheless to imagine 1 January 2011 becoming a symbolic moment for this Arsenal team, the day perhaps that they came of age as Premier League contenders. Certainly, an argument can be constructed to support the theory.
Here was an occasion, at the scene of Martin Taylor's leg-breaking, morale-shattering challenge on Eduardo in February 2008, where Arsenal faced a Birmingham side intent on defending a proud home record and prepared to be as robust as they felt necessary, which they demonstrated as early as the eighth minute, when Roger Johnson's sliding tackle sent Cesc Fabregas spinning.
Would Arsenal shrink away? Not this time. Where Manchester United had been held last week – where Chelsea had lost in November – this Arsenal side remained true to their purpose, kept the ball at their feet and played their way to a comprehensive victory. This was an Arsenal, one could conclude, that had grown up, accepted reality and could live with it.
Arsène Wenger needed little encouragement to embrace the idea. "Our away record is the best in the league. No one can dispute that," the Arsenal manager said. "And in England when you want to travel well you have to be physically resilient and I think we've shown that since the start of the season.
Yet there is another interpretation of Saturday's events, equally valid, that might argue that the comparison between January 2011 and February 2008 proves nothing, that the only difference, really, is that where Eduardo suffered a horrific injury, the sight of which profoundly – and lastingly – affected players and manager, Fabregas came through unscathed.
Not that the tackles were identical. Whereas Eduardo had been in possession, and still striding forward, when Taylor's sliding boot collided with his shin, this time Johnson had the ball and was trying to retain it, however recklessly, when he launched himself.
Fabregas, more streetwise, saw it coming and was at least trying to avoid full contact, which might have been enough to spare him serious damage. This time, then, there was no snapped limb to sicken onlookers. Indeed, Fabregas recovered so completely he went on to combine brilliantly with Samir Nasri to create both his side's second-half goals, the first a 13th of the season for the Frenchman, the second eventually going in – a little ironically – off Johnson's boot after Ben Foster had saved from Fabregas.
The act of violence likely to have more repercussions was committed by Lee Bowyer, who landed a boot on Bacary Sagna's knee in an incident unseen by referee Peter Walton. The Birmingham player could face a three-match ban if the Football Association charges him on television evidence.
Walton, meanwhile, was central to another small but potentially critical difference between 2011 and 2008, when Arsenal's black mood was compounded as James McFadden's last-minute penalty levelled the scores for Birmingham. And City should have had a penalty this time, when trailing only to Robin van Persie's deflected first-half free-kick, after Van Persie controlled the ball with his arm.
"Decisions like that change games," Alex McLeish, the City manager, reflected. "Arsenal would still have been the classier side, but we might have had a point, might even have sneaked a win."
Scorers: Arsenal Van Persie 13, Nasri 58, Johnson og 66.
Subs: Birmingham Hleb (Beausejour, 59), Zigic (Bowyer, 69), Phillips (Jerome, 79). Unused Taylor (gk), Jiranek, Fahey, Derbyshire. Arsenal Denilson (Wilshere, 79), Arshavin (Walcott, 79). Unused Szczesny (gk), Squillaci, Eboué, Rosicky, Bendtner.
Booked: Birmingham Johnson, Ridgewell, Dann; Arsenal Djourou.
Man of the match Nasri. Match rating 7/10.
Possession Birmingham 48% Arsenal 52%.
Shots on target Birmingham 1 Arsenal 11.
Referee P Walton (Northants). Att 24,341.