De Boer, working as a BT pundit, had said when discussing Rashford, who was making a first league start in 2018 against Liverpool: "It's a pity that the manager is Mourinho because normally he's an English player you want to give him time and he can then make mistakes".
'If he was coached by Frank he would be coached how to lose because he lost every game.
The 20-year-old striker has scored 12 goals in 40 appearances for the Red Devils this term but De Boer claimed he should be starting more matches under Mourinho.
"In 2007-08 it was an unreal partnership, they have been huge players I have looked up to and watched how they perform to try to put into my own performance."
Rashford was given his first-team debut under Louis van Gaal in the 2015/16 season and has since scored 31 goals in 111 games in all competitions. "You want to see this player every week".
Asked if he feels he has the conditions to bring a fourth European Cup to Old Trafford, Mourinho said: "Not yet, but when a team reaches the last eight anything is possible. The more you do, the easier the results come on the pitch.", Rashford said after the Liverpool game.
That record was brought up as Mourinho went after the Dutchman, having been irked by the former Palace manager saying it was "pity" for Rashford to be playing under the United boss given his preference for short-term success over player development.
A quick couple of tip-toe steps to help his gain get the momentum and strength behind his shot were exactly the thing Cristiano Ronaldo does - and did with Dynamo Kiev - which was in this instance more than enough to get the Manchester United fans buzzing. He starts some and comes from the bench in others.
The local lad burst onto the scene as an 18-year-old, scoring a brace on his Premier League debut against Arsenal. We have eight matches still to play and 24 points to play for (in the Premier League). Of course not but he is a player that we trust.
"He started and had a good match and I'm not just talking about goals". I'm really happy with Marcus'.