Former Crystal Palace and Ajax boss de Boer was a guest on BT Sport's Premier League Tonight show on Saturday and claimed that perhaps it was "a pity" the Portuguese coach was in charge of the young Englishman.
"When you are in the last-16 it looks really, really far but when you are in the last eight you start smelling semi-finals, the feeling is that you are amongst the best".
"He started, he had a good match and I'm not just speaking about scoring goals because, for me, the analysis of a performance is much more than analysing the number of goals or assists", said Jose Mourinho, as reported by the club's website.
During Mourinho's press conference for Tuesday's UEFA Champions League clash against Sevilla, the Manchester United boss was asked if Marcus Rashford had done enough in the 2-1 win over Liverpool to retain his spot in the team.
His club and global teammate Lingard, who has scored 13 goals in 37 games this term, admits he has been winding Rashford up during his spell out of the side in order to keep his spirits high.
Yet, some labelled him as a fringe player simply because Alexis Sanchez's arrival gave Mourinho the opportunity to rest a 20-year-old who had played nearly every game for United.
"We try to give the best to the kid's education". "I have to be honest and give the credit to the people of the academy that were responsible for his formation, to Mr. [Louis] Van Gaal, who was responsible for his first season". He plays for United many matches, he starts some comes from the bench for others. "I'm really happy with Marcus".
"I think that Gareth Southgate doesn't mind that I say a couple of minutes of our conversation were about Marcus", said Mourinho.
"Of course not. He's a player we trust".