Conte was angry at a lack of spending over the summer as he sought to strengthen his title-winning squad.
And he claimed depth had been an issue after a series of midfield injuries.
Conte said: “I think when you play every three days it's very difficult but every coach tries to make the best decision for his team.
“It's important to have rotation otherwise you risk having players who are very tired, in this case Cesc.
“He's played every game from the start of the season because don't forget, Bakayoko and Drinkwater were injured.
"We played in China and Singapore with just Kante and Cesc, and then N'Golo was injured but Cesc continued to play.
“He played every game, and played very well in every game, so I took this decision and it was important because when you give a new player this type of chance, in a big game, it shows the coach trusts all of his players. I can count on Drinkwater."