Andre Santos gave the hosts the lead in the 21st minute but they failed to keep the pressure as Cavin Lobo's second-half brace ensured Kolkata's lead at the top grew bigger.
"We created chances like our previous matches but could not cash on to it and once was unlucky that post came in the way to deny us the second goal which should have sealed the game in our favour. But we will try hard and try to win our next match," said Zico after the loss.
"The other thing that happened which is more serious is that one of our players said that he was beaten by the coach of the other team. Pires said he was punched on the face by the Atletico coach and it is very shameful," said a "concerned" Zico.
"I am telling you what my players told me and I didn't see that myself but I don't think that Pires will not lie and say something that didn't happen. And when the team entered the field in the second half, they were very nervous and during the half time we were only trying to control their nerves and calm them down," he added.
