Yea, the match is unpredictable, because no one can tell which of them is the favorite. Real Madrid are always something else when it comes to UCL. They take the league so personal as if it is their birth right. On the one hand, Atletico is is a good form and wouldn't accept defeat easily. We saw the best of them in one of their previous match against Barcelona.
Because Real Madrid always has a difference when playing in the Champions League, it will provide quite a fierce competition in their match later because Atletico Madrid who this season has also improved their performance will also provide a very tough resistance for Real Madrid in that match. But I still have faith in Real Madrid because Ancelotti always has the best way to make the Real Madrid team stronger in the Champions League.