Chelsea manager Antonio Conte praised the potential of Ethan Ampadu following the teenager's accomplished display in the dramatic EFL Cup quarter-final win over Bournemouth.
Conte's side prevailed 2-1 at Stamford Bridge thanks to Alvaro Morata's stoppage time winner, which came immediately after Dan Gosling had equalised for the visitors.
Ampadu was booked in the second minute of the match for a late tackle on Jermain Defoe, who was subsequently forced off with an ankle injury.
But the teenager walked the tightrope well and was the most influential of a defensive trio that also featured Gary Cahill and Antonio Rudiger.
"It is not simple for a defender to play after a yellow card in the second minute but he showed great maturity and personality," Conte told reporters at his post-match press conference.
"I said in the past that this player, despite his young age, has shown great maturity.
"I do not like to make gifts for someone. If they deserve it, I am ready to play with very young players. Why not? Ampadu deserved to play this game, and against Everton and Huddersfield in the league.
"Now he has to stay calm. He could have a great future, but he has to continue in this way, to improve and to work."
Chelsea appeared set for a comfortable progression to the semi-finals when Willian opened the scoring in the 13th minute.
Morata's late intervention eventually sealed a place in the final four, although the striker's yellow card amid the ensuing celebrations means he will miss Saturday's trip to Everton.
"He is a big loss for us, especially because we have to play a tough game against Everton. It is a pity," Conte said.
"[But] we must be happy with this achievement, to reach a semi-final in one of the two cups in England. It is great for us, especially because we reached the semi-final with a lot of rotation.
"I am very happy because I have had a good response from my players."