As soon as the match ended in a 1-1 draw, two flag-waving East Bengal supporters invaded the Mohun Bagan pitch that led to an uproar in the home camp as stones and verbal abuses were hurled in plenty with about 500-odd supporters in attendance.
Being an age group match, the security was not adequate as the mounted police and the Kolkata police struggled to control the incident.
Describing this as a poor display of the sport, Mohun Bagan's I-League-winning coach Sanjoy Sen, who was at the ground, told PTI: "It was everything but football."
"I never expected this from the U-18 boys. They should have been more skillful with ball passing and receiving but it was an atrocious display."
More From This Section
Refusing to comment on the crowd trouble, he said: "These incidents in a derby is pretty common these days."
According to the referee, the striker had fired in the ball before he blew the whistle.
Mohun Bagan brought the game on an even keel with a goal from Deepak Tangri in the 89th minute and crowd trouble soon took the centre stage and spilled over outside the stadium.
The draw enabled Mohun Bagan remain at the top of the 'Kolkata Zone' table with seven points from three matches.