On hearing these comments, the Special One was enraged, and fired back a reply slating De Boer for his poor record in the Premier League, while adding that he had no right to bad-mouth another manager.
"I read something, some quote from the worst manager in the history of the Premier League, Frank de Boer saying it's not good for Rashford to have a coach like me".
The former Netherlands defender, who worked alongside Mourinho at Barcelona when the United manager was Louis van Gaal's assistant, didn't win any of his league games as Palace manager and his team didn't score a goal.
Not trusting young players is a stick Mourinho has been beaten with since his first spell at Chelsea but a stat has been unearthed that will change your mind on everything you've heard about Rashford recently. And Marcus is having these experiences.
"I think we are not one of the best teams in the competition, but I think when a team arrives in the last eight anything can happen. Analysing a performance for me is more than number of goals or assists, and for me I'm really happy with Marcus". Does he play every match from the start? No?
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. Of course not but he is a player that we trust.
Southgate has discussed Rashford's progress with the man at the helm at Old Trafford, and Mourinho insists the England boss is satisfied with the current state of affairs.
"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".
OECD warns of trade war threat to global economic rebound
On the likelihood of a backlash against Mr Trump's threatened tariffs, he added: "This could obviously threaten the recovery". Rebounding global business investment would keep global trade growth at about 5 percent this year, the OECD forecast.
Kim meeting only if N Korea fulfills promises: WH
Some experts are concerned that North Korea could be seeking to delay worldwide action while strengthening its nuclear program. Nevertheless, there is no word from Pyongyang about when the talks that the regime is said to have proposed will take place.
Palestinian PM escapes Gaza explosion
The ties between Palestine and the United States have been witnessing rising tensions since last October, and peaked when U.S. He said that despite the attack he remained committed to Palestinian unity and would continue to come to Gaza.