كتب : Hatem Maher
The precious victory sent the Bavarian giants through to the semi-final.
Egyptian forward Mohamed Zidan stunned the home crowd when he put Mainz ahead in the 22nd minute from the penalty spot.
A header by Peruvian striker Pizarro leveled the score nine minutes from time to send the match into an extra time.
Paolo Guerrero put Bayern in front in the fourth minute of the extra time after meeting Bastian Schweinsteiger's cross with a powerful header into the back of the net.
Petr Ruman equalized for the visitors in the second period of the extra time before Pizarro sealed the victory for Bayern five minutes before the end after he fired a powerful shot past Mainz keeper.