Middlesbrough became the latest club to lose out to the skill and goalscoring flair of Frenchman Christophe Dugarry as they lost their third successive game.
With only seven wins in 42 games at St Andrew's, the north-east club never appeared likely of improving their dismal record as Birmingham finally assured themselves of Premiership football again next season.
Dugarry, who is thoroughly enjoying his first taste of life in the Premiership, put Birmingham on the winning path with an 18th minute goal.
Stephen Clemence recorded his first ever goal for Birmingham with a 40th minute strike from a free-kick won by Dugarry.
To cap a runaway win Australian Stan Lazaridis popped up to head home a rare goal in the 80th minute.
Middlesbrough were sadly off colour in the absence of Juninho and Birmingham were able to record one of their easiest wins of the season but they were deeply indebted to the Dugarry influence.
There was an early confrontation between Robbie Savage and George Boateng, the outcome of which was that referee Mike Dean read the riot act to Savage pointing out who was in charge of the game.
Savage, however, was not put out of his stride and maintained his relentless challenges despite some finger-wagging by Boateng.
The skill of Dugarry was a feature but Middlesbrough's defence did not appear to be in any trouble although their pre-occupation in playing the offside trap ultimately led to their downfall.
In the 18th minute, with Dugarry seemingly in an offside position, the Frenchman collected a long pass from Clemence and coolly slotted the ball past a transfixed Mark Schwarzer.
It was a well-merited lead as Birmingham mounted most of the attacks with Bryan Hughes and Clemence both industrious in their bid to maintain a strong attacking pressure on Boro.
Malcolm Christie made some determined attempts to get Boro back into the game but he could not find a way past the solid Kenny Cunningham who has played a leading role in Birmingham's recent revival.
Birmingham virtually settled the game and their Premiership status in the 40th minute when Dugarry was brought down on the edge of the area by Ugo Ehiogu.
While Middlesbrough were attempting to sort out their defensive wall, Clemence lashed home his first goal for Birmingham since his move from Spurs last January.
But Birmingham had a let-off just before the break when Ehiogu was given a free header from Frank Queudrue's corner. Fortunately Hughes was on the line to clear.
Middlesbrough attempted to get back into the game but to no avail and their fate was really settled in the 80th minute when a high right-wing cross was headed into the far corner of the net by Lazaridis.