The Blues trail the French side 3-1 after the first leg of the Champions League quarter-final, but Mourinho has faith in their ability to overcome the odds at Stamford Bridge.
"I believe and my players believe. That's the most important thing," said Mourinho.
"I think if Paris is knocked out, it will be a big disappointment for them. If we are knocked out, it's something that, in this moment, lots of people are expecting.
"We have to enjoy the risk of the situation. At 9.30, we can be out and we know that we have this risk. But at 7.45, we have chances to be in the semi-final.
"We have to be at 7.45 with a smile on our faces, go in, play, give everything. At 9.30, let's see what happens. But at 7.45 we believe that we can do it.
"I think we are going to win, really. In the end of the two legs, I think we are going to score more goals than them.
"In this moment it's 3-1, I think in the end it can be 4-3 or 5-4. If I don't think that way I don't go on Tuesday. And I go and I'm happy to go."
Mourinho also called on the Chelsea supporters to contribute to another memorable occasion.
"If they (the fans) can push us a little, that push is welcome," he said.
"But everything starts with us. And I think if we can show that we can do it, I think they will come with us."