It was in Germany where Jovic caught the eye of Europe's elite with a statistically ridiculous season.
Jovic built on his debut campaign at Eintracht with an explosive sophomore return, scoring 27 goals in 48 appearances and spearheading the club's run to the Europa League semi-finals.
Real won the race for his signature last summer, forking out €60m and a six-year contract for the 22-year-old.
Jovic has since struggled under the bright Bernabeu lights, scoring just twice in 24 appearances, most of which have come off the bench.
This has lead to some calls for Los Blancos to sell the youngster, but after watching the Serbia international every day training, Muller insists it would be a terrible idea.
"For me he is one of the best strikers that I have trained with in my whole career," the Western Sydney Wanderers forward told Tribalfootball.com.
"In every training, in the game, last year in Frankfurt he was the best, for me, in the whole league. He needs to work more, but he is young and can learn.
"Now you see it's different from Frankfurt to Real Madrid, this is a big, big step.
"But I think he needs time and I hope they give him time and then he can become a big striker in Europe."