Sports director Leonardo explained PSG's embarrassing 1-0 league defeat at battling 10-man Stade Reims on Saturday by saying: "Maybe we have a team made for Europe, based on talent and passing quality, not for that kind of game."
PSG indeed looked a different side from the one who beat Valencia 2-1 away in the first leg and their chances of success in Wednesday's home game have been hurt by suspensions to striker Zlatan Ibrahimovic and midfielder Marco Verratti.
The Ligue l leaders' defeat by Reims was the second in a row against a lowly team after they were humbled 3-2 by Sochaux before back-to-back wins against arch rivals Olympique Marseille in the league and French Cup.
PSG coach Carlo Ancelotti blamed a bad pitch at Reims for the loss but there will be no excuses on Wednesday on their Parc des Princes turf, where 37-year-old David Beckham could make his first Champions League appearance since 2010 with AC Milan.
The former England captain, who signed a short-term deal with PSG in January, could start the match unless Ancelotti decides to field Clement Chantome or Thiago Motta returns from injury.
The Italian coach is likely to change his centre back pairing with captain Thiago Silva in the running to feature for the first time in more than seven weeks after recovering from a thigh problem.
The Brazilian's return would be a boost to PSG, who could have all but sealed their last-eight qualification in Valencia if they had made more of their domination before allowing the Spaniards to pull a goal back late on.
Valencia are missing usual centre backs Adil Rami and Ricardo Costa.
France international Rami, who netted their 90th-minute goal in the first leg, is still recovering from a muscle strain in his left thigh while the Portuguese defender, who has suffered a minor muscle problem, has been left out of the squad.
"We know how Paris play. I watched their last two games and they often rely on the counter attack, allowing the other team to have the ball and breaking very well," Valencia full back Jeremy Mathieu said.
"Valencia's tactics are to pressure as much as possible and spend as much time in the opponent's half as we can," added the Frenchman, who returned from a lengthy injury break at the weekend and could play alongside Victor Ruiz at centre half.
Valencia drew 2-2 at home to city rivals Levante on Saturday, conceding late to miss out on a victory that would have lifted them above Malaga into fourth in La Liga.
Paraguay forward Nelson Valdez reckons the European Cup is a good benchmark for Valencia.
"I think the PSG match will be crucial for us to discover what level we are at. There are only strong teams left in the Champions League now, so we have to show we belong here," he told UEFA's website (www.uefa.com).
"The best music I know is the Champions League anthem. Personally, it always gives me goose bumps, listening to that music and standing in line before the game - even sitting on the bench. It means I am at a good club and I am a part of this."
Paris St Germain: 30-Salvatore Sirigu; 26-Christophe Jallet, 2-Thiago Silva, 13-Alex, 17-Maxwell; 29-Lucas, 32-David Beckham, 14-Blaise Matuidi, 27-Javier Pastore; 7-Jeremy Menez, 11-Ezequiel Lavezzi
Valencia: 13-Vicente Guaita; 12-Joao Pereira, 22-Jeremy Mathieu, 18-Victor Ruiz, 17-Andres Guardado; 24-Tino Costa, 21-Daniel Parejo; 8-Sofiane Feghouli, 10-Ever Banega, 7-Jonas; 9-Roberto Soldado
Referee: Milorad Mazic (Serbia)