Paris Saint-Germain coach Laurent Blanc admitted he is realistic about the size of the task facing his side as they attempt to overturn a 3-1 Champions League quarter-final, first leg deficit away at Barcelona on Tuesday.

The French champions were torn apart by Barca's star front three of Luis Suarez, Neymar and Lionel Messi at the Parc des Princes last week, just as they were when they last visited the Camp Nou in the group stages in December.

And while Blanc is confident PSG can pose the Barca defence problems, he believes stopping the South American trio is an almost impossible task.

"I'm fairly realistic. Yes we believe we can do it, but like you, we know that it is extremely difficult," he said on Monday.

"We can say that we have nothing to lose. I think we will have the opportunity to score, but the big problem is that we can't concede and against Barcelona that is almost impossible.

"We must defend well, we say that every time we play them, but we have conceded in every game because they have incredible offensive players.

"I hope we can show we are better than what we showed in the first leg."

The visitors will at least be boosted by the return of their own top scorer as former Barca striker Zlatan Ibrahimovic returns from suspension.

"He will have a big impact. He is a player I have never doubted," added Blanc.

"He loves these type of matches, so he will help us. It is always better to have very good players and goalscorers, as we saw in the first leg."

Marco Verratti also returns from a ban to take his place in midfield, but Thiago Silva and Thiago Motta both miss out due to injury.

And midfielder Javier Pastore is hoping Ibrahimovic and Verratti's presence can prove the difference from one week to the next.

"It will be a very difficult game, but the only good thing is that we don't have anything to lose. We come into the game with a negative result, but we have added two fundamental players to the team and they will give us a lot.

"We believe because that is our job and football is a game in which you have the possibility to win or lose. For our fans and ourselves we need to play very well and win the game."

However, the Argentine international dismissed French legend Eric Cantona's recent comments that he and not his compatriot Messi, who scored his 400th Barcelona goal at the weekend, is the best player in the world.

"Everyone has their opinion and I thank him publicly for what he said, but I don't believe the same.

"I think he likes good football and not just goals, but the stats of Messi and (Cristiano) Ronaldo are incredible, unattainable numbers."