With relegation from the National Football League staring them in the face, Mohun Bagan, on Wednesday, lodged a complaint with the All India Football Federation against Benjamin Silva, the referee in their match against arch-rivals East Bengal, alleging that they were denied two penalties.
The letter, written by club assistant general secretary Balaram Chowdhury, was sent to AIFF president Priya Ranjan Dasmunshi.
Chowdhury said he is hoping for a positive response from the AIFF.
Earlier, Bagan coach Amal Dutta had gone hammer and tongs at the referee, saying his club was denied two clear spot-kicks.
"Due to his poor supervision, my players have suffered mentally. So, I think, my club has done the right thing by protesting," Dutta said.
Former champions Bagan, who are facing relegation with 18 points from 19 outings, lost Sunday's derby encounter against arch-rivals East Bengal 0-1.