Chelsea had looked to be heading for victory in the first leg of their Champions League last-16 clash on Tuesday after Willian finished brilliantly in the 62nd minute at Stamford Bridge.
However, Christensen’s pass across his own box was punished as Lionel Messi scored to give Barca an away goal in the tie.
Asked about the mistake for the goal, Chelsea boss Conte said: “I think Christensen’s performance was a very good performance, an incredible performance. We are talking about a player who is only 21 years old here.
“It’s great that he is able to play this game with maturity and personality. I am very happy. He was one of the best players tonight.
“It is very difficult to pick one player or another player but I think Christensen played a top game. I am very pleased with his performance.”