The coach believes his side can turn the tie around after being defeated at home, though Jeremy Mathieu, who is just returning from injury, will deputize at center back
The Liga team will have to turnaround a 2-1 deficit in the second leg at Parc des Princes, and the former Olympiakos boss knows that it will be difficult due to the two away goals scored by Carlo Ancelotti's side.
"We are really going to do everything to qualify tomorrow," he told a press conference on Tuesday.
"Nothing is for certain, so we believe in our chances. It is normal that PSG are the favourites for tomorrow, but we'll give 100 percent to stay in this competition."
The Spanish side has been hit by a number of injuries in defense, meaning fullback Jeremy Mathieu will operate in a more central role, and Valverde believes the 29-year-old has the ability to succeed in a more unfamiliar berth.
"The team knows we will have to score several goals. We will have to be quick in attack, while also defending well, as they have good forwards," he added.
"We need to find the good balance. I have a few options in defense, but I am very happy with Jeremy Mathieu’s performances. He has a lot of qualities and has played some good matches."
PSG will be without Zlatan Ibrahimovic due to suspension and Jeremy Menez because of an injury.