Atletico Madrid are never an easy opponent for Real Madrid in La Liga and Champions League. It is classic of any derby in football, even you are a stronger team, you might fail in a derby match. Atletico Madrid in this season are not weak by showing their quality, strength and competitiveness in both La Liga and Champions League. They lead Real Madrid in La Liga and are ready to beat Real Madrid in Champions League as well.
Atletico are a tougher opponent now, you can even see it in the way they continue to stay close to Barcelona in La Liga, while Real have problems with their defense, which is not always able to play well. And Atletico's attack looks much better now, they have great forwards, so maybe Real remains the favorite, but not by a very large margin. Real's attack is also very good, and Atletico will have to rely on their defense.