PSG lead Group F by two points and will be favourites against bottom side Milan after hammering the Italians 3-0 at the Parc des Princes a fortnight ago.
But a 4-1 reverse at Newcastle United in early October and a series of close calls against Ligue 1's lesser lights has highlighted how a team capable of steamrolling the opposition at home can be got at on the road.
"I'm an optimist by nature. I'm optimistic because the players are in good form and want to put in a good performance," Luis Enrique told reporters in Milan on Monday.
"I'm happy with my team's attitude."
PSG's evening will be complicated by the hot reception goalkeeper Gianluigi Donnarumma will get from a capacity crowd at one of Europe's most intimidating stadiums.
Donnarumma enraged Milan supporters when he left as a free agent just over two years ago, and their hardcore supporters are reportedly preparing a pre-match display in honour of their public enemy number one.
Fans will also wear the number 71, which in Naples and the surrounding areas from where Donnarumma hails stands for a man with no honour, while a wave of whistling will roll down the stands every time he touches the ball.
"We've laughed about it together... it often happens in football that you go from love to hate," said Luis Enrique.
"He needs to look past it and not look at it as an added difficulty."
Milan are in something of a mess in the lead up to Tuesday's clash, with injuries piling up and one win in their last six matches in all competitions.
Saturday's 1-0 home defeat at the hands of lowly Udinese led to a cascade of boos from home supporters and coach Stefano Pioli taking public blame for a series of disappointing results.
Milan are yet to even score a goal in the group but Pioli said on Monday that he believes that his struggling team can pull off a surprise win against Kylian Mbappe and company.
"If we play the way we did in the first half at Napoli (where Milan led 2-0 at half-time before drawing 2-2), then we have a chance of winning," said Pioli.
"This is certainly a match which could be the turning point for our Champions League campaign... we want to show that Milan isn't the team seen on Saturday."
