The ex-Real Madrid boss lavished praise on former rival Pep Guardiola for the way he has improved on the side Louis van Gaal and Jupp Heynckes built.
The Bavarians annihilated all teams in their path last season, winning the Champions League, Bundesliga title and DFB-Pokal before Jupp Heynckes stepped aside for the ex-Barcelona boss to take the helm in the summer.
Nine months on, Bayern sits on top of the German league by 20 points, has one foot in the last eight of Europe at Arsenal's expense, and has a domestic cup semifinal to look forward to.
Mourinho, who tussled with Guardiola for two seasons in La Liga when he coached Real Madrid, thinks that Die Roten have improved even more under his tutelage, though he credited former bosses Louis van Gaal and Jupp Heynckes for getting the ball rolling at the Allianz Arena.
"I think Bayern are getting better and better," the coach told Yahoo. "I think this new Bayern started with Louis van Gaal. He started cleaning the team of all the players and starting with Thomas Muller, Bastian Schweinsteiger, Holger Badstuber and Toni Kroos, he was starting with these people and took the team to the Champions League final in 2010.
"After that came Jupp Heynckes, who did unbelievable work, and the team kept becoming better and better and they won the Champions League, and now Guardiola also is a fantastic coach and I think [they are] naturally improving. Over the last few years as a club they are doing very well."