With a £30million price tag looming over his head, it has been a somewhat unspectacular start to Willian's Chelsea career, with only two goals to his name so far.
However, the 25-year-old has still done enough to keep last season's Player of the Season Juan Mata out of the starting XI.
"When I arrived things went slowly," Willian told the Daily Express.
"You need to get used to the other players, the way we play, the philosophy of the coach."
That influence of Mourinho has not been lost on the former Shakhtar Donetsk and Anzhi Makhachkala midfielder, who was full of praise for the role the Portuguese has played in his Blues initiation.
"Mourinho is a great coach," he added. "He has guided me with what he wants. He gives me freedom, but he likes his players not to neglect their defensive work.
"He expects and demands a lot. But this is normal from a coach who wins things."