Osasuna coach Jose Luis Mendilibar believes Real Madrid are getting back to their best ahead of the La Liga clash between the teams.
Jose Mourinho's men have been struggling domestically this season and sit third in La Liga, 16 points behind arch-rivals Barcelona.
But Mendilibar, 51, says they are still a force to be reckoned with.
"Real Madrid are still one of the best teams in the world. They are just returning to their best form again and it will be very difficult to get a good result," he told reporters.
"They are great in every area and do not seem to have any weaknesses. They are impressive tactically, physically and technically.
"They showed against Sociedad that they are mentally tough as well, and we will have to be at our best to get something from this game."