Ottmar Hitzfeld has dismissed suggestions Pep Guardiola has been a failure at Bayern Munich.
Guardiola will leave the Allianz Arena at the end of the season for Manchester City having never won the Champions League in his three seasons in Bavaria.
Bayern have been knocked out in the semi-finals of the competition in each of their three campaigns under the former Barcelona boss.
He has won three successive Bundesliga titles and also claimed the DFB-Pokal, a title Bayern will attempt to reclaim in this year's final, in 2014.
But Bayern's Champions League elimination at the hands of Atletico Madrid has led to some to dismiss his reign as a failure, claims Hitzfeld - who led Bayern to five Bundesliga titles and one Champions League success across two stints as coach - has been quick to discredit.
Asked if Guardiola has been a failure at Bayern, Hitzfeld told Bild: "There is only one answer to this question: No, he hasn't. Guardiola isn't treated fairly. He improved Bayern and the whole Bundesliga.
"Everyone who does not recognise it is sensational that Guardiola led Bayern to three Champions League semi-finals in a row is clueless.
"Normally a team who won the treble [as Bayern did in 2013] falls into a hole. They are not that hungry anymore, you ease up.
"But Guardiola protected Bayern from that case and made the players greedy. He instilled Bayern with a passing quality like never before. He made them play high-speed football. I think Guardiola will only get the appreciation he deserves in Germany in a few months. Often you only realise how good someone was when he is already gone.
"I also don't agree with the critics who claim Guardiola did not identify himself enough with Bayern. If you saw him on the sidelines you know how much passion he gave for this club."