De Boer, who was sacked by Crystal Palace earlier this season after losing his four league games in charge without a goal scored, claimed on Saturday that it was “a pity” that a talented young player like Rashford was managed by Mourinho.
Rashford scored a match-winning brace in Manchester United’s 2-1 win over Liverpool on Saturday after making his first league start since the turn of the year.
“It’s a pity that the manager is Mourinho because normally [Rashford’s] an English player you want to give him time and he can then make mistakes,” De Boer said while appearing as a pundit on BT Sport. “But Mourinho is not like that. He wants to get results.
“’If he has one or two not good games, he puts him out,” he added. “He’s a player, he’s very young, he needs games, but he’s so talented. You want to see this player every week.”
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While previewing United’s Champions League knockout tie with Sevilla, Mourinho shot back at De Boer and claimed that if he coached Rashord, the youngster would only “learn how to lose”.
“I read some quote from the worst manager in the history of the Premier League, Frank de Boer – seven matches, seven defeats, zero goals. He was saying its not good for Marcus Rashford to have a coach like me.
“If he was coached by Frank he would learn how to lose because he lost every game.”
De Boer managed Palace for four league games – not seven, as Mourinho claimed – though he does hold the record for the lowest points won by any manager in the history of the Premier League. His only other game in charge of Palace – a EFL Cup second round tie against Ipswich Town – ended in a 2-1 victory.
Before starting from the off on Saturday, Rashford had been limited to just 173 minutes of league football since Boxing Day, while he only made a 15-minute cameo in the first leg against Sevilla three weeks ago.
The 20-year-old’s only starts of 2018 had come against Derby County and Yeovil Town in the FA Cup, which led England manager Gareth Southgate to meet Mourinho at United’s Carrington training ground to discuss his lack of playing time.
“I try to give the best to the kid,” Mourinho added on Monday. ”I have to be honest and give the credit to the people of the academy that was responsible for his formation, to Mr Van Gaal who was responsible for his first season.
“But if you go to his numbers and how many matches he played with me last season and this I would say probably he’s in the top five players with more matches in the two seasons.
“I think that Gareth Southgate doesn’t mind that I say a couple of minutes of our conversation was about Marcus and he knows what Marcus can give. I think we are all on the same page.
“He’s played for Manchester United many matches, he starts some, comes from the bench others. He is 20 – 21 years old. I’m really pleased with everything. Does he play every match from the start? No, of course not, but he’s a player we trust.”