Paddy McCarthy’s charges found themselves 1-0 down at half-time, but they made the most of two straight red cards for the visitors in the second half, scoring four times through the clinical Brandon Aveiro.
Even when facing 11 men in the first period Palace were on top, creating a number of opportunities they were unable to put away.
The Eagles' first shot on target came in the clash's opening minute as they ran out of the blocks with real intent. Skipper Sean Robertson won the ball high up the pitch and released John-Kymani Gordon, who saw his low drive parried away to safety.
Gordon was central to the host’s attacks in the early exchanges, showing strength and tight control in holding the ball up, while also offering a threat in behind with his pace.
The Birmingham defenders frequently resorted to fouling the young striker, and consequently the Eagles won a succession of free kicks close to the box. From the second of these, Robertson saw his effort cannon back at him off the crossbar.
Despite their dominance, Palace were giving the ball away carelessly, and – seizing on one such instance – the Blues’ Rhys Hilton flashed a shot inches wide of goal. When the visitors missed another clear opening, Palace were required to re-establish a foothold in the game and ultimately they did so, with Aveiro, TQ Addy and Gordon all going close.
These missed chances however seemed to affect the Eagles’ morale and concentration, and with half-time approaching, the visitors made them pay. A testing cross from the right ended up at the feet of Hilton, who lashed home to make it 1-0.
The turning point came after half-time when the Blues’ Kane Thomson-Sommers was sent off for clattering into Martin Onoabhagbe. Almost immediately, Palace capitalised on their numerical advantage as Aveiro slalomed his way into the area before pulling his side level.
Things then got worse for the visitors, as Tate Campbell received his marching orders from the referee after another overzealous tackle. The hosts made full use of the extra space available and as the south London sky grew brighter, so too did Palace's fortunes. An error from Blues 'keeper Josh Bradley-Hurst let in Aveiro, who made it 2-1 with precision.
With the home side struggling to secure three points by adding a third to their half of the scoreboard, Aveiro took matters into his own hands in the 86th minute, this time creating a yard of space and firing a stunning strike into the top corner from 25-yards. Minutes later, he followed the thunderous effort up with another rasping drive - thus capping off a fantastic second-half display.
Palace: Russell, Trehy (Omilabu 57), Chamberlin-Gayle, Gurung (Jessup 87), Onoabhagbe, Parris, Robertson (Smith 87), Addy, Gordon, Aveiro, Bello.
Unused subs: Carter, Ajayi.
Birmingham: Bradley-Hurst, Baker, Roberts, Walker, Forrest, Gordon, Hilton (Traore 82), Campbell, Okoro, Hurst (Mayuba 67), Thompson-Sommers.
Unused subs: Clayton, Knight, Djurovic.