While summarising the game for BT Sport, De Boer claimed it was a "pity" that Mourinho was responsible for Rashford's development given his prioritisation of results and lack of inclination to nurture younger players. Normally he's an English player, you want him given time, he can make mistakes.
Rashford has had to make do with limited first-team opportunities under Mourinho this season, particularly following Alexis Sanchez's arrival from Arsenal in January, but the England worldwide returned to the starting line-up on Saturday afternoon to score both goals in a 2-1 win over Liverpool. If he was coached by Frank, he would learn to lose because he lost every game.
The United boss had an acerbic response to hand when he addressed a news conference ahead of Wednesday's (AEDT) UEFA Champions League showdown with Sevilla, seemingly holding De Boer responsible for Palace's slump extending to seven winless and scoreless matches as Roy Hodgson picked up the pieces at Selhurst Park.
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The Saints were enduring a torrid spell under the Argentine, with just one win coming in their last 17 Premier League games. Mark Hughes has been named as the "leading candidate" for the vacant Southampton manager's position, not Marco Silva .
De Boer suggested Mourinho was not the right manager to nurture Rashford's talents, with Mourinho quick to pour scorn on the views of a coach who has failed in his last two jobs at Inter Milan and Palace. I try to give the best to the kid.
"But if you go to his numbers and how many games he played with me".
"It is a pity that the manager is Mourinho". We won 2-1 against Liverpool and at the end of the game there were some who said it was a failure. So I imagine if we were knocked out it would be considered a disaster. Rashford himself has come out recently and said that he has had to develop in training as opposed to on the pitch and if his performance on the weekend is any indication of his development then the 20-year-old is doing just fine. "When you're in the last 16 it looks really far but in the last eight you start smelling [the] semi-finals".
"I think we were all on the same page".