Antonio Conte backed Tiemoue Bakayoko after taking him off at half-time against Leicester.
Pedro scored an extra-time winner at the King Power Stadium to secure a trip to Wembley to face Southampton in the FA Cup semi-finals.
Bakayoko, recalled to the side by boss Conte, has struggled since his summer move from Monaco.
But Conte insisted the only reason he took the French midfielder off was because he picked up a yellow card and leaving him on would have risked him being sent off.
“It was a decision because he took a yellow card,” Conte said.
“We are talking about a player with great physicality and I think in a game like this you have to try to prevent a second yellow card.
“Only for this reason I decided to take him off after the first half.”
Conte praised his players for battling through a tough 120 minutes just four days after their Champions League defeat at Barcelona.
Some were feeling the effects, including Willian and Andreas Christensen, who were taken off later in the game.
Conte, whose side were beaten by Arsenal in last season’s final, said: “Willian was very tired. I think also that today he played a fantastic game. I’m very pleased with his commitment.
“We decided to take this decision because he was very, very tired. It was the same with Christensen.
“After a game in the Champions League it wasn’t easy for us to play 120 minutes.
“We showed great will and a great desire to fight and to reach the semi-final.
“We must be pleased with the character we showed against a really good team.
“This trophy is very important for this country. Last season it was a pity to lose in the final. This season our target is to reach the final again.
“And if we reach the final, I want to change the final result compared to last season.”