Ancelotti’s side will need to overturn the deficit if they are to defend the Copa after second-half goals from Raul Garcia and teenage defender Jose Maria Gimenez handed Atletico the advantage in their round of 16 tie.
Wednesday’s outcome followed Real Madrid’s 2-1 defeat at Valencia in the Primera Division and their 4-2 loss to AC Milan in a mid-season friendly in Dubai last month.
“To speak of a crisis is exaggerated,” Ancelotti told his club’s official website. “Of course, we are not happy and we want to return to winning ways as soon as possible.
“We cannot forget that there is still 90 minutes left to play in this tie.
“Atletico have the advantage but we still have to play at home and anything can happen.
“We will try with all our strength to progress. We haven’t thrown the tie away and we still have an opportunity to progress.”
Ancelotti defended his decision to leave out Cristiano Ronaldo from his starting line-up against Atletico.
“Cristiano was tired and that is why he didn’t start,” Ancelotti said. “I didn’t want to risk him and that is the reason why he only played in the second half.
“We struggled to create opportunities but it was not the fault of Gareth Bale or Karim Benzema.
“It’s difficult to play against Atletico because they defend well and are very organised at the back.”
Real host Espanyol on Saturday before facing Atletico on January 15 in the return leg of the Copa at the Santiago Bernabeu stadium.
The European champions are one-point clear of Barcelona at the top of La Liga and have a game in hand.