Before Saturday evening they had lost just once at home in La Liga and were proud owners of the league's meanest defense.
Their cause was further strengthened when Jose Mourinho made eight changes and, even more so when Radamel Falcao headed them in front inside five minutes.
Derby day gloom was soon restored for them though, unfortunately.
Before 10 minutes was up, Real Madrid were level. Angel Di Maria's free kick deflecting off Juanfran into the full back's own net.
Di Maria would later score the winner too. His clever run was picked out by Karim Benzema, and the Argentinian international did the rest.
It wasn't all about Di Maria, who became a father this week, though. Here are the player ratings for the rest of Los Blancos' team.