The Spanish coach has warned that his side "are in a dangerous situation" and has called on them to step up their performances if they are to reach the Champions League final
The Bavarians have been struggling to hit their top level in recent weeks and have won only one out of their last five official games, much to the frustration of Guardiola.
"If we play in Madrid like we have done recently, we have no chance of reaching the final," Guardiola said at a press conference.
"If we play like we have done in the last three league games, we won't be reaching any finals.
"We're in a dangerous situation. When the focus isn't there, then the head is slow and everything happens a little slower."
Bayern last met Madrid in the Champions League in 2011-12, when the Bundesliga champions beat their Spanish rivals on the away-goals rule before eventually losing the final to Chelsea at the Allianz Arena.
The first leg of this season's semi-final tie is scheduled to take place at Santiago Bernabeu on April 22.