PSG head into the second leg of their last-16 tie trailing 3-1 and will be without world-record signing Neymar for the clash at Parc des Princes (7.45pm).
The Brazil superstar is sidelined with a fractured metatarsal but he has assured Messi that his team-mates are confident of progressing to the quarter-final stage, according to Spanish publication Don Balon.
It is claimed Neymar has reiterated his promise to Messi that PSG will meet Barcelona later in the competition.
PSG showed flashes of promise in the first leg at the Bernabeu.
Adrien Rabiot fired them ahead in the 33rd minute before Cristiano Ronaldo levelled the scores on the brink of half time.
PSG had a number of chances after the break but Ronaldo and Marcelo struck late on.
According to Don Balon, PSG’s players are convinced they can win the second leg and the tie.
Former Real Madrid winger Angel Di Maria is reportedly motivated to impress and he is expected to occupy Neymar’s role in the starting XI.