Bayern Munich coach Pep Guardiola is counting on Frenchman Franck Ribery's anger to power them past Real Madrid in their Champions League semifinal second leg on Tuesday despite the winger's recent slump in form.

Ribery had a sparkling season until Bayern clinched the Bundesliga title with seven games to spare.

The team has since looked like a pale shadow of its former scintillating self that broke record after record en route to the league title with Ribery having lost his spark down the left wing as Bayern notched just two wins in their last five league games.

"Franck Ribery is extremely important for this club, for the team," Guardiola told reporters on Monday ahead of the second leg following their 1-0 defeat in Madrid last week. "He was playing angry against Bremen (in Bayern's 5-2 win on Saturday).

Franck needs this aggression, he needs to play angry.

"He keeps fighting and that is why fans love him.

He is one of the best players in Bayern history, he  as always performed at the highest level and we need the best Ribery."

Bayern were again unconvincing for much of the game against Bremen before an explosive second half saw them charge past their opponents with Ribery also on target.

Guardiola, in his first season in charge, is looking to lead Bayern to an unprecedented back-to-back Champions League win and should they make the final they would equal Juventus' record of having reached three consecutive finals in this competition (1996-98).

They will, however, need to score against a team that last week successfully managed to keep the Bayern attack under complete control despite the Germans' overwhelming possession.