In an interview with The Telegraph, Mourinho lamented the absence of robust professional support during his stint, which he feels that Ten Hag is now benefiting from.
"My relationship with [former chief executive] Ed Woodward was good. Good as in the personal point of view," Mourinho said. "Even now we send an SMS. But from a professional point of view, it was not the best. I am who I am. I am a football man. Ed comes from a different background and what Ten Hag has in his time at Manchester United I didn't have.
"I didn't have that level of support. I didn't have that level of trust. So I left sad because I felt I was in the beginning of the process. In some moments, I felt if they trusted me and believed in my experience things could be different."