Carlo Ancelotti admitted that fatigue was the key factor in Real Madrid suffering a 4-2 Spanish Cup defeat to Atletico.
"Nobody deserved to lose. There were some schoolboy errors and that was the key," the boss is quoted by the club's official website.
"We were at a disadvantage against Atlético because they have had a week to prepare for the game and physically they had a bit more energy.
"But we competed until the 120th minute and it didn't look like we were tired. Now we have two weeks to work well and improve our fitness."
Regulation time ended in a 2-2 draw, with Madrid fighting back from 1-0 and 2-1 down. However, better physical shape worked in Atleti's favour in the end and they scored two goals in extra time.
The Whites have played five games this month already, with the Almeria game scheduled for January 21. After that, Madrid will have a week of rest.
