Barca and PSG will meet this month in the round of 16.
Asked for a prediction, Mandi said: "Who will qualify? For me, it will depend on Lionel Messi.
"It will depend on him, if he is in good shape. If he wants to qualify Barça, he will because he is an exceptional player.
"Of course, PSG should not be underestimated. But if Messi does his job, things will be able to switch to Barça's side."