The Parisians will be without attackers Edinson Cavani and Neymar for the Champions League last-16 first leg clash.
"I was asking him [Di Maria] some questions about Manchester United," Draxler said.
"I won't tell you what he said but he will be ready for tomorrow.
"He's a big player. He has a lot of respect for the club [United], there's nothing terrible in what he said but it was between me and him, so I won't tell you right now.
"He's in good form, we'll need him tomorrow, especially without Cavani and Neymar, hopefully he'll have a great performance tomorrow."