In the same month of their formation, the club participated in their maiden tournament in the Hercules Cup, which was a seven-a-side tournament. On 11 August 1920, the club played their first match both in the tournament and in their history against Metropolitan College, which they went on to win 4–0 . East Bengal went on to win the tournament, announcing the arrival of a club which would go on to break many records in the future. The club also won Khagendra Shield in 1921. Following this, the club became affiliated with the Indian Football Association (IFA) and entered league play in the IFA Second Division. The club finished placing third in their maiden season in the league. The first match between East Bengal and Mohun Bagan took place on 8 August 1921 in the Cooch Behar Cup semi-final match, which didn't turn in the favour of either of the teams as it ended in a goalless draw. It was an unofficial derby at that time.