And while Scot McTominay and Jesse Lingard offer a particular set of skills that perhaps fit into Jose Mourinho's somewhat rigid style more adequately, Marcus Rashford is proving to be the WOW element and the dazzling factor Manchester United have not had in a long time.
De Boer, who has also managed Ajax and Inter Milan, suggested on Saturday that Rashford should play more often.
After Saturday's 2-1 victory over Liverpool in which Rashford scored United's goals, De Boer said it was a "pity" Mourinho was the 20-year-old's manager.
"But Mourinho is not like that".
It's never a good idea to get into a war for words with Jose Mourinho.
After all the discussion of whether Rashford is fading away under Mourinho at Man United, the Special One threw him a start against Liverpool and he kindly paid him back with a brilliant brace to win the staunch rivalry. When you are younger than I am and you are learning the game I think you do need it. Whether it's when he rushes forward, tracks deep into his own half or stands up to players nearly double his age to defend his teammates, there is something rather curious about Marcus Rashford that makes him just like Cristiano Ronaldo.
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Mourinho, clearly angered by De Boer's comments, fired back at the ex-Netherlands star by branding him the Premier League's worst manager of all-time.
"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".
"If Marcus would be coached by Frank, he would learn how to lose". Marcus I have to be honest and give the credit to the people of the academy that were responsible for his formation and to Van Gaal for his first season in the first team. I said that before the Liverpool match when many of you were maybe not expecting him to start. He starts some and comes from the bench in others.
The first goal against Liverpool was just another proof of this claim.
Mourinho believes United will have a chance of winning the trophy if they progress. He was saying its not good for Marcus Rashford to have a coach like me.