The Brazilian is eagerly anticipating Wednesday's match at Camp Nou and has little doubt PSG can cause the Blaugrana problems
Rai feels Barcelona looked vulnerable in defence during the 2-2 draw at the Parc des Princes last week and he expects them to have similar issues in the return.
"I think that Paris Saint-Germain will get chances to score over there. I dare even say that I am sure they will score at Camp Nou," the Brazilian was quoted as saying by Le Parisien.
"In the first leg, Barcelona looked shaky at the back on a number of occasions and it will be the same in the return.
"Paris Saint-Germain can cause Barca's defence problems with their speed and feeling for position."
Wednesday's match is scheduled to kick off at 20:45CET in Catalunya.