Jose Mourinho has unwavering belief that his Chelsea side will overturn a two-goal deficit to advance to the Champions League semi-finals at the expense of Paris St Germain.
Mourinho, twice a Champions League-winning boss, has faith in his side's ability to respond in adversity and upset the odds after a 3-1 quarter-final first-leg loss in Paris.
"Reasons to believe? I think the reasons are not important," Mourinho said.
"I believe and my players believe. That's the most important thing.
"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. And I go and I'm happy to go."
"I think we are going to win, really"
Mourinho insists Chelsea were more culpable than PSG were good in the loss at Parc des Princes last Wednesday.
"In Paris we would expect Paris to play very well to control the game, to have the ball, to be very dangerous," Mourinho added.
"We were dangerous to ourselves, because we scored half of the first goal, we scored the second goal and we scored the third goal.
"Plus our goal, we scored three and a half goals in that match. It was not Paris that played very well."
PSG boss Laurent Blanc is adamant his side will not be cowed by Chelsea and will play their own game.
"We can't just be content with sitting back and letting Chelsea come on to us," Blanc said.
"Our ambition is to go out and try to cause them problems. We're used to taking the game to the opposition.
"Look at our statistics in the Champions League - we've always scored.
"That's a significant statistic. Chelsea are going to try to score, but Paris St Germain will as well. That's our mentality.
"We've not come here to suffer, we've not come here to have Chelsea just dictate the game to us and to dominate us.
"We know that the best approach to take is to have the ball and to create chances.
"That's the role of a top team, to be able to dominate the game away from home. Ultimately the game will come down to who has the ball and how well they're able to use it."
PSG have lost just once by two clear goals in their last 110 fixtures and Blanc believes they can exploit holes when Chelsea attack.
"We believe in certain things and I've always believed in this particularly philosophy, that taking the game to the opposition is the best way of winning trophies," Blanc added.
"Our philosophy is an attacking one. We like to keep the ball and we try and pose problems to our opposition.
"If we really want to be a top-level European side then we need to be able put this philosophy into practice at the Parc des Princes and away from home.
"We're going to have potentially some issues in the first 20 minutes.
"Chelsea are going to be very aggressive and come out to try to score.
"It's up to us to try to be very calm and even try to counter-act Chelsea's play."
Mourinho could be prepared to risk striker Samuel Eto'o, who has scored all 11 of his goals this season at Stamford Bridge but has missed the last three matches with a hamstring injury.
PSG are without talisman Zlatan Ibrahimovic with a thigh problem.