Gilberto revealed it was never going to be easy for Emery to follow in the footsteps of his predecessor.
"I think many people wanted this change and the time has finally come," he said.
"I always said it was going to happen at some point and now we have a new manager.
"We have to support him because it is not going to be easy for him.
"He has a difficult task because he is replacing a man who changed the history of the club.
"And he needs to understand quickly the way the club works and the mentality.
"It's very difficult."