Atletico claimed a 3-1 semi-final win at Stamford Bridge on Wednesday and the upshot was a lethargic first-half display that allowed struggling Norwich to bed in for a point.
The result means a victory for either Liverpool or Manchester City in their remaining games will end Chelsea's Premier League title hopes.
“I think that when we lose the Champions League semi-final you know you are not realistically in the title race," he said.
"I think the mental energy disappears, the focus disappears, you start thinking more about what next than what you have to do now and that was reflected in my opinion in the first half.
"The first half was the consequence of that state of mind. In the second half we were much, much better and better enough to win but we didn't."
In light of recent disciplinary trouble for himself having commented on officials' decisions and a six-match stadium ban for assistant Rui Faria, Mourinho opted to keep his council on this occasion.
"Hazard, I saw in the game but to confirm I had a quick run to my office and I arrived in time to watch and to go back to the dugout laughing," he added.
"The other one I didn't see and it’s better not to speak about it. My assistant is in jail and I don’t want to comment."
