Roberto Mancini saw his Manchester City side warm up for the derby in devastating style.
But perhaps more importantly for the Italian manager they cemented fourth place in the Barclays Premier League table, which brings the reward of a Champions League slot.
Nedum Onuoha scored his first league goal of the season and Emmanuel Adebayor also weighed in with a brace.
With Carlos Tevez scoring his 27th of the season from the penalty spot and also getting a touch to Onuoha's header to score his 28th, City secured a comfortable victory.
They have now scored 14 goals in the last three games which will put them in good heart for the match against Manchester United on Saturday.
Guest of honour at the game was former City goalkeeper Bert Trautmann, 86, who broke his neck in the victory against Birmingham in the 1956 FA Cup final.
He saw City dominate the first half and Adebayor found the side netting after being released by Tevez, who was looking for the return pass.
Birmingham again found themselves on the back foot after 14 minutes with Tevez firing wide following good link up play involving Craig Bellamy and Adebayor.
The visitors then got themselves in a muddle at the back but Adebayor could not take advantage and failed to test Maik Taylor.
City maintained the momentum and Adebayor turned quickly in the area after 33 minutes only to see Roger Johnson and Taylor combine to block his shot.
Five minutes later Tevez made the breakthrough with his 27th goal of a remarkable first season at the club.
The Argentina striker scored from the penalty spot after Scott Dann was adjudged to have bundled over Adebayor.
Tevez stepped up and sent Taylor the wrong way with his effort to put City in the driving seat.
They went 2-0 ahead in the 40th minute when Onuoha was left unmarked as Adam Johnson swung in a corner. The full-back thought he scored with a firm downward header and wheeled away in delight but Tevez got the last touch before the ball crossed the line.
However, Birmingham pulled a goal back two minutes later with Cameron Jerome heading home following a cross from James McFadden.
City responded immediately with Adebayor making it 3-1 in the 43rd minute when he got on the end of Bellamy's delivery with Taylor out of position.
They almost extended their lead in the 50th minute after Onuoha got on the end of a free-kick from Bellamy but saw his header go over the bar.
Play switched back down the other end and Keith Fahey should have scored when Shay Given failed to deal with a cross but the striker headed wide.
Tevez then squandered a good opportunity in the 60th minute after Bellamy had put Roger Johnson under pressure.
The ball broke to the City striker and he raced on only to get a heavy touch and Taylor was able to gather it up.
Birmingham were making a decent fist of it, however, and Fahey rattled in a shot that was blocked by Given's legs.
Then Tevez thought he had scored in the 64th minute only for Taylor to claw away his excellent free-kick from 20 yards.
Tevez saw his close range effort parried by Taylor in the 71st minute but Bellamy spooned the rebound into the crowd.
City went further ahead in the 74th minute with Onouha shrugging off a couple of half-hearted challenges before sending a shot beyond the despairing Taylor.
Birmingham were being stretched and Adebayor secured his brace two minutes from time after running from deep before beating Taylor.Reuse content