They went ahead through Lukas Nmecha in the 49th minute, with the 27-year-old converting after good work from Noah Okafor.

However, Birmingham were able to force extra-time when Patrick Roberts’ deflected strike sailed into the net.

In that period, both sides missed chances.

Dominic Calvert-Lewin came close to firing Leeds through, only to see his effort saved at the death.

With nothing to separate the two teams, it was left to the dreaded penalty shootout to decide which of the sides would be in Monday’s draw for the fifth round.

The first four spot-kicks were all scored, only making the atmosphere inside St Andrew’s even more tense.

However, the fifth penalty of the shootout ultimately swung the pendulum in Leeds’ favour.

Tommy Doyle, who had enjoyed a terrific match in the middle of the park for Birmingham, saw his effort saved by Lucas Perri – with the Leeds star diving to his right to spark wild celebrations in the away end.