Evra, who played against Marseille many times during his days with Monaco, knows from experience how tough an encounter Wednesday's first leg clash will be.
"They're going to be confident of beating us, there's no doubt about that," Evra told ManUtd.com.
"It's a dangerous game for us because we are favourites and in a way Marseille have nothing to lose. I've watched some of their games this season and you can see they are a good team and they have a great manager in Didier Deschamps, who was my coach at Monaco.
"He is not afraid of any team and I know he will get his players motivated before the game so they play with no fear. They will give 100 per cent but we are Manchester United and we need to show our qualities. It will be a tough game, but if we are professional and do our job we have a great chance of going through."