Maradona, who inspired Napoli to two Serie A titles during his time at the club, was at the Santiago Bernabeu for the round-of-16 first leg, which Madrid went on to win 3-1.
"We know it's going to be difficult but we will try," Reina said. "There are still 90 minutes remaining at the San Paolo stadium. It's going to be a beautiful game at the San Paolo, Real can expect a warm night.
"With the warmth of our stadium, we will be 11 brave men who have nothing to lose. We have to believe we can turn the tie around because we can beat Madrid 2-0 at home."
Reina added that the loss will not affect his team, who sit third in Serie A, nine points adrift of leaders Juventus, and play away at Chievo on Sunday.