Barca are all but out of the Champions League ahead of the second leg of their last-16 tie at Camp Nou on Wednesday, following their drubbing at the hands of the French champions in the first-leg.
And Madrid great Raul does not think Luis Enrique's men will pull off a miracle - instead feeling it is his former club, rather than Luis Enrique's side, who have a history of storied fightbacks in Europe.
"If any club is capable of such a comeback then that would be Real Madrid because that is their specialty," Raul told Le Figaro.
"Barcelona would have to have an exceptional game and at the same time Paris Saint-Germain a horrible one, so I think it is very difficult.
"If PSG play like they did in the first leg, then it will be nearly impossible for Barcelona to score four or five goals against them like they do against opponents in LaLiga."
Holders Madrid, meanwhile, are already in the quarter-finals after defeating Napoli 6-2 on aggregate on Tuesday.