Barca visit the Parc des Princes for a clash between the two favourites to qualify from UEFA Champions League Group F, with the Spanish giants - and talisman Messi - in ominous form.
Luis Enrique's team are yet to concede a goal in seven competitive fixtures this season, scoring 18 goals in the process of claiming six wins.
In contrast, French champions PSG have failed to hit the ground running, with coach Blanc coming under increasing pressure after a run of four 1-1 draws in their last five outings.
Four-time world player of the year Messi has looked reinvigorated by the arrival of former Celta Vigo boss Luis Enrique, and the Argentina captain surpassed the 400-goal mark for club and country with a brace in Barca's 6-0 demolition of Granada on Saturday.
And Blanc is in little doubt as to who poses Barca's primary threat when they travel to the French capital.
"Everyone knows who Messi is - that's what an exceptional player is made of," said the ex-France coach.
"He's able to score, he's able to take the ball past three or four and score [and] he's also able to create chances for his team-mates to score and allows them to play great football.
"When I see his position on the pitch, I think about another great player playing here with us in Paris in this central position, but who also likes to get involved in the match."
