Ferguson was left fuming by two key second-half decisions as Russell refused to award a blatant penalty before failing to send off Birmingham player Callum Reilly.
The Posh chief was adamant Russell should have pointed to the spot when wideman Nathaniel Mendez-Laing was sent crashing by City full-back Mitch Hancox soon after the restart.
And Ferguson's mood was worsened when Russell chose not to show a second yellow card to the already-booked Reilly for a cynical trip on Kane Ferdinand.
Both incidents occurred after Posh trailed to a Nikola Zigic opener 10 minutes before the break.
A deflected second goal from Chris Burke 10 minutes from time eventually sealed Posh's fate.
Ferguson said: "If you're asking me whether or not the officials are good enough, the answer is nowhere near at this level. There were two big decisions in the game and the referee got both of them wrong as far as I am concerned.
"I see absolutely no reason why a forward would choose to go down when clean through and Nathaniel is adamant the Birmingham lad caught him. The assistant referee was 10 yards behind play so in no position to give a penalty while the referee clearly chose not to give one.
"I asked the referee why he didn't give the Birmingham lad a second yellow card and he said his foul was an accident, but again that's not how I saw it."