The second-leg of their quarter-final with the Ligue 1 champions begins with Chelsea 3-1 behind after defeat in Paris, however Mourinho is confident his squad can turn the tie around.
Laurent Blanc's men arrive in London without their main striker Zlatan Ibrahimovic, who suffered a thigh injury in the first leg, and the Portuguese manager hinted his absence could help Chelsea score more goals than their opponents.
"If you ask me if I think we will win tomorrow, yes I think (we will)," said the manager at Monday's press conference. "I think we are going to win.
"At the end of the two legs I think we will score more goals than them. If I don't think that way, I won't go (to the game) tomorrow.
"We are going to score more goals than them. By the end of the two legs it can be 4-3, 5-4.
"I believe, and my players believe, that is the most important thing."
The 51-year-old insisted his side have nothing to lose, and urged his players to enjoy the possibility of making the last four.
"The players have to show their quality, confidence and ambition," he added.
"We have to enjoy the risk of the situation. At 21:30 (full time, local time) tomorrow we can be out and we know that we have this risk.
"But at 19:45 (kick-off) we have chances to be in the semi-final.
"If PSG tomorrow are knocked out it is a big disappointment for them. If we are knocked out, it is something a lot of people expect."
