Willis Plaza (30th minute) put Churchill ahead before Dicka (45+3, 70th) restored parity in the closing seconds of the first half.
Dicka then found the winner late in the second half to push Mohun Bagan into the next round.
The game began on a slow note with most of the first half being played around the midfield.
Churchill Brothers took the lead when Plaza scored off a calculated pass from Nicholas Fernandes.
A series of attacks from Mohun Bagan thereafter kept Churchill Brothers on their toes, but a reckless tackle from Nicholas on Mohun Bagan's Sheikh Faiaz helped the Bengal club earn a penalty during first half injury time.
Churchill Brothers goalkeeper Ricardo Cardozo blocked the initial attempt from Dicka, but the Cameroonian striker punched in the rebound to bring Mohun Bagan back on level terms.
The second half began with Mohun Bagan pressing hard from the very first minute. A real opportunity came their way when Faiaz attempted a shot at the goal in the 48th minute but failed to give the Bengal outfit the lead.
Thereafter Mohun Bagan made several attempts to score but were kept at bay by the well organised Churchill defence.
It was only in the 69th minute when a free kick from Cameron Watson and a header from Akram Mograbi followed by a brilliant finish from Dicka gave Mohun Bagan the lead.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
