Sanchez struggled to replicate the form he showed during his Arsenal career after swapping the Emirates Stadium for Old Trafford in January 2018 in a deal that involved Henrikh Mkhitaryan.
A lack of consistency, coupled with persistent injuries punctuated his Manchester United career, restricting him to just 37 appearances with five goals.
And Mourinho, who was at the helm during the Chilean’s first year at United has revealed the former Barcelona forward failed at Manchester United because he was unhappy.
“Sanchez… I felt him [to be] not a happy man,” Mourinho told The Telegraph.
“And I think in every job you have when you are not happy it is not so easy to perform at every level. And maybe I am wrong.
“Maybe it was me who was not capable to get into him and to get the best out of him.”
Despite disclosing why the new Inter Milan man was unsuccessful at the Old Trafford, Mourinho believes Sanchez will rediscover his happiness and form at his new club.
“As a manager sometimes you have the capacity to get the best out of the players and other times you are not successful in that approach.
“But the reality is that I always felt [of Sanchez], ‘a sad man’.
“So probably in Italy, he will recover this. I hope he can. I always wish well to every player.”
Hoping to regain his lost form, the 30-year-old has joined Serie A outfit Inter Milan on a season-long loan and is expected to make his debut for the Nerazzurri in their home game against Udinese on Saturday.
