Ralf Rangnick suggested that he was embarrassed to see Manchester United fail to score against Everton on Saturday.
The Red Devils suffered a 1-0 loss to the Toffees at Goodison Park, dealing a significant blow to their hopes of finishing in the top four this season.
The loss comes just days after relegation-threatened Everton lost 3-2 to a Burnley team currently stuck in the Premier League's drop zone.
What has been said?
Rangnick admits he found it difficult to explain his team's failure against Frank Lampard's men, especially since the same team were beaten by Burnley a few days prior.
He told reporters: "When we conceded, we lost a little bit of our composure and maybe also a little bit of our confidence and, if you don't score against a team like Everton, with all respect to a team that conceded three goals against Burnley, you cannot expect to get anything out of it.
"We've been talking about that for the last 10 minutes. I totally agree. It is not so difficult to see.
"If you don't score in 95 minutes against a team that conceded three goals against Burnley, and we scored three goals against Tottenham at home, it's difficult to explain.
"For us, as a coaching staff, it's not so easy to understand why we didn't create more chances in a game like this."
What next for Manchester United?
United are now in seventh place and sit three points behind Tottenham and Arsenal, who are currently the leading candidates for a place in the Premier League's top four.
Rangnick's team have taken just one point from their last three matches in the English top flight.
However, they take on the Premier League's bottom team Norwich next week, followed by a trip to Anfield to face title contenders Liverpool three days later.
Four days after that, United will meet fellow top-four contenders Arsenal in north London.