Blues U18 coach Hassan Sulaiman told the club's website: "I worked with Alfie at Under-13s.
"He was in many ways the same type of player he is now. He was a bit quieter because he was still finding his feet at Chelsea after joining from QPR, but he held himself and his team to high standards, had leadership qualities and always gave 100 per cent.
"There was a transition coming from QPR because at Chelsea we often had more of the ball. We worked with him to refine his technical skills so he could play through a press confidently with a range of passes.
"He did take real joy from making tackles, making blocks, stopping his opponent, defending well. Those defensive instincts are so important and they are not always easy to come by now because everyone glamourises playing out from the back rather than the art of defending."
Loan chief Ed Brand coached Gilchrist with the U18s and said: "Something that has stood out with Alfie is he has genuine desire to defend his goal.
"Of course, he can play as well and is strong passing off both feet, but you can't underestimate having that desire in a defender.
"Then you've got his professionalism and leadership why I made him captain numerous times. There are no airs or graces with Alfie. He gets his head down, he does his work and contributes to the team.
"He's always been that way. That's credit to him but also his family - that he is a level-headed, mature, down-to-earth kid."