"I read something, some quote from the worst manager in the history of the Premier League", the United boss said.
The 20-year-old has played in 27 Premier League matches this season, however just a handful of those appearances have seen him complete the full 90 minutes, with new signing Alexis Sanchez seen by many as yet another threat to any sort of continued inclusion. He wants to get results, ' he said on BT Sport.
"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 learn how to lose because he lost every game".
Pierre-Emerick Aubameyang frustrated by Europa League absence
Victory for sixth-placed Arsenal took them to 48 points, eight points behind defending champions Chelsea. Watford play in the Premier League next Saturday with a trip to Liverpool (17:30 GMT).
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 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.
The midfielder - who surprisingly started the goalless first leg on the bench in Spain - was injured on the eve of the Liverpool clash and was conspicuous by his absence from the section of training open to the media on Monday.
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.
MIT scientist charts fake news reach
Aral and his team were stunned by how much faster fake news stories proliferated through the vast social media network. They determined which stories were false and which were true by fact-checking them on several reliable news sources.
"Sevilla and Brighton are more important than Liverpool". When a team gets into the last eight, the feeling is you are among the best and anything can happen.
"I try to give the best to [Rashford]", Mourinho said.
"I don't know (if he can play), we don't know yet, but he trained a little bit after you left". I'm really happy with Marcus'.
"Does he play every match from the start?"
RBs Murray, Stewart to visit Lions
It's no secret that the Lions have struggled mightily at the running back position for the last handful of years. If Detroit chooses to pass on both Stewart and Murray, there are other choices on the free agent market .