Thierry Henry scored his 200th goal for Arsenal as Arsene Wenger's side got back to winning ways at Birmingham and ended a miserable week on a high.
Arsenal's Mathieu Flamini beats Birmingham's Jiri Jarosik
Following Sol Campbell's absence and defeat to West Ham, Henry lifted the Gunners' mood, firing home after being released by Cesc Fabregas.
Togo striker Emmanuel Adebayor had earlier headed the visitors in front from close range.
Blues striker Emile Heskey was sent off for two bookings late on.
After such a week to forget, Wenger would have welcomed the slice of luck that presented his side with their opener.
There was nothing fortunate about the build up as Henry slipped the ball through to Abou Diaby and he fired a shot across the box.
Martin Latka had tried to cut it out but goalkeeper Maik Taylor was forced to make a save. The ball ballooned into the air and Adebayor was perfectly placed to nod home from almost on the line.
After a depressing African Cup of Nations campaign with Togo, from which he only returned on Wednesday, the debutant would have appreciated the lift as well.
Until that point, the Blues had enjoyed the territorial advantage and Jiri Jarosik tested Jens Lehmann with a right-foot shot that the German keeper tipped wide.
Heskey's power was testing a rookie Arsenal defence, which had an average age of 20, but the Gunners should have been even further in front before the break.
As Birmingham pushed forward, they were playing into the hands of their visitors, who relish attacking on the break.
On one such occasion, Adebayor was sent through and should have done more to test Taylor than offering a weak effort that the keeper had little trouble in collecting.
When the second goal did arrive, it came from a more familiar source.
Fabregas released Henry to race through on goal, and there was nothing Taylor could do about the Frenchman's cool finish.
Matthew Upson missed a great chance when his header hit the post but Birmingham were unable to battle back, despite the introduction of former Brentford FA Cup hero DJ Campbell as a substitute.
To make things worse, Heskey was sent off with seven minutes later for a second bookable offence after he crashed into Mathieu Flamini.
Birmingham manager Steve Bruce:
"I thought we started brightly and got at them but Arsenal showed that little bit of quality.
"But we were disappointed with the second goal which we could have kept out.
"I can understand Emile's frustration because, if you watch the two challenges, he is looking at the ball on both occasions.
Arsenal manager Arsene Wenger:
"We showed a lot of character in a very difficult game and there were some performances that are very encouraging.
"We also had a lot of quality and effiecency as well so I am very pleased.
"You know you are going to get a physical battle with a lot of experience but we handled it well."
Birmingham: Maik Taylor, Melchiot, Latka, Upson (Bruce 88), Gray, Pennant, Izzet (Campbell 70), Butt, Jarosik (Forssell 69), Sutton, Heskey.
Subs Not Used: Vaesen, Tebily.
Sent Off: Heskey (83).
Booked: Heskey, Sutton.
Arsenal: Lehmann, Flamini, Senderos, Djourou, Larsson, Fabregas, Silva, Diaby, Reyes (Hleb 79), Henry, Adebayor.
Subs Not Used: Almunia, Pires, Bergkamp, Walcott.
Booked: Henry, Larsson, Diaby.
Goals: Adebayor 21, Henry 63.
Ref: M Riley (W Yorkshire).