The Barcelona forward is yet to hit top form at the showpiece event, but Mandanda knows what Messi is capable of ahead of Saturday's clash in Kazan.
"We need to defend well, close to each other, even though Messi is able to do everything," he told a news conference.
"We know that, we are warned. We have players in our team who played a few times with him or against him in La Liga.
"We know what we would expect on Saturday but we have the weapons to defend well and to hurt them."
Argentina struggled through the group stage in Russia, needing Marcos Rojo's late winner against Nigeria to advance.
Mandanda said he was yet to study Jorge Sampaoli's side, but he is wary of Messi.
"I have not made a proper analysis of Argentina's style yet. We played a game yesterday [a 0-0 draw against Denmark], since then I have not checked," he said.
"But we all know they have a player who is capable of everything.
"They have quality. It could come from everywhere. They had a hard time qualifying themselves, but they did. It's always a strong team to play against."