Portsmouth, beaten 5-0 on their previous visit to St Andrew's, certainly gained sweet revenge as they produced another composed performance to record their sixth successive away win.
They were handed their latest success on a plate and it was an unfortunate mistake by Birmingham's debutant goalkeeper, Richard Kingson, which put them on the winning path to increase their unbeaten run to nine games.
Kingson, surprisingly preferred to Maik Taylor, allowed a tame looking shot from Sulley Muntari slip through his fingers after 34 minutes which compared to Scott Carson's mistake for England earlier in the week.
Although Kingson later made a couple of good saves, the damage had been done, and Portsmouth sealed their latest win on the road when Nico Kranjcar capped a fine week with the second goal.
The Croatian scored direct from a free-kick seven minutes from time after scoring the opening goal against England on Wednesday.
It was a bad result for Birmingham watched by their smallest crowd of the season.
There were few encouraging signs for Birmingham whereas Portsmouth are hitting the high spots with the likes of Sylvain Distin, Sol Campbell and David James showing top-class form.
Manager Harry Redknapp has put together a more skilful and successful side since the disastrous 5-0 defeat and this was highlighted by Portsmouth's overall performance.
Goalkeeper James is in good form and Pompey fans voiced their opinion in no uncertain terms when they chanted "still England's number one."
Birmingham obviously wanted to produce a top-class performance in view of the off-the-field events, but Portsmouth always appeared to have the slight edge.
Everything appeared to be going to plan until the 34th minute when disaster struck struggling Birmingham.
There was no apparent danger when Benjani slipped a short pass to Muntari, who fired in an angled shot from the right and the ball slithered through the hands of the unfortunate Kingson.
It was a massive setback for Birmingham and put Pompey well and truly in the driving seat.
Only Mikael Forssell appeared to be of any real danger to the Pompey defence in which Campbell and Distin were in commanding form.
Birmingham's brave fight was extinguished when Kranjcar slammed home his 82th minute free-kick.