Maurizio Sarri believes Callum Hudson-Odoi is a "great player" but fears excessive pressure could ruin the teenager's promising career.
Chelsea winger Hudson-Odoi, who has been frustrated in his quest for regular first-team football, underlined his potential by stepping off the bench to seal Thursday's 3-0 Europa League win against Dynamo Kiev.
Supporters at Stamford Bridge had called for the talented 18-year-old to be brought on before his 78th-minute introduction and he justified the hype with an impressive cameo.
However, Blues head coach Sarri once again warned against hastily thrusting Hudson-Odoi into the limelight.
"I think to have pressure when you are 18 is very dangerous for a player," said the Italian.
"You can lose the target. When you're 18 the target is to improve – to improve, tactically, mentally and physically.
"So, it's dangerous for him. I don't like to speak about him for this reason.
"Now I think we need to improve without the pressure of the media, without the pressure of the fans, without the pressure of the club.
"He (doesn't) have to do anything to convince me because I am convinced that he is a very great player."
Hudson-Odoi handed in a transfer request in January amid offers from Bundesliga champions Bayern Munich.
He has now scored four times this season but is still awaiting his first Premier League start.
"He is in my mind for every match. In England, I think he's the only to be born in 2000 to have played 16 matches in the first team," continued Sarri.
"In my opinion a player at 18 years cannot be at the top yet.
"He needs to improve because he will be able to arrive at the top only at 22 or 23, like every other player."
Hudson-Odoi's late strike, which followed goals from Pedro and Willian, means Chelsea have one foot in the quarter-finals of the European competition ahead of next week's second leg in Ukraine.
Sarri added: "We were able not to concede a goal at home, which is very important in this competition.
"So the result is OK now."