Buffon said that Juventus intend to take advantage of Real's early relative poor form, which has seen them slip five points behind both Barcelona and local rivals Atletico Madrid.
"They say that Real are going through a tough time, but the reality is that with the players that they have they can easily change that," Buffon told reporters.
"I do not wish to be unsporting, but I hope they are not at their best against us. A win against Real would give us great confidence as we need to embark on a winning run in Europe."
Buffon revealed that he turned down a move to Barcelona in order to join his current club.