It will be very amazing if Real Madrid will restore their weakness in performance.
I think Real Madrid performance isn't that weak. Mostly, they were defeated by big teams (both in UCL and La Liga). But unfortunately, they got some draws when they played against average teams. Well, Real Madrid performance is rather inconsistently during this season.
Their winning the game is already what we all have predicted because, even with the weak performance, they are supposed to win Osasuna. They really played a good performance more than the last game that they played against AC Milan, even though that was a game in the Champions League.
We can't compare this match and the match against AC Milan. The level of Osasuna and AC Milan is quite different. AC Milan is surely in a higher level, Osasuna is a mediocre team only. Sure, Real Madrid have no difficulty to beat Osasuna with big scores. Real Madrid played at home, Real Madrid also has a stronger squad. There is no way that Real Madrid loses points in this match.