Neymar shapes as a huge threat to Madrid as PSG prepare to visit the Santiago Bernabeu for the first leg of their Champions League last-16 tie on Wednesday.
"To play against Neymar, there is no magic formula," he said, via AS.
"You just hope he doesn't have his day. I hope he doesn't have his day on Wednesday."
Having struggled in La Liga this season, the Champions League is set to be Madrid's last chance at another trophy this campaign.
Carvajal insists there are no favourites for the tie against PSG, who are flying high in Ligue 1.
"There is no favourite in a battle like that. The knockout stages are very even, they are decided on little details," he said.
"We will try to not commit any errors and to get it right in the area."