Eto'o proved Inter's matchwinner at Stamford Bridge and was left unimpressed by Chelsea's performance.
Eto'o told The Sun: "I expected more from the Blues but think pressure and nerves affected their performance.
"I am so happy. I hadn't scored since December and this one was so important.
"Mourinho's plans were perfect. No one could doubt our superiority. This match was sensational for me but I was sad about the red card for Drogba.
"I understand his frustration. This is another season when it is impossible for my brother Didi to win the Champions League."