Erik ten Hag admits he does not know why Manchester United have defended so poorly throughout their dismal start to the season.
Ten Hag's side have conceded 14 goals in their last five games in all competitions after slipping to a 4-3 defeat at Bayern Munich in their Champions League opener on Wednesday.
The Bayern collapse came after Brighton won 3-1 at Old Trafford in the Premier League to pile pressure on United boss Ten Hag.
With a clash against struggling Burnley looming on Saturday, Ten Hag desperately needs to shore up United's leaky defence.
Alarmingly for United fans, the Dutch coach conceded he is still trying to get to the root of the problem.
"We have shown that we can do it because last year we had the most clean sheets in the Premier League because of the team, because we defended very good as a team, so we have to get back to that standard," Ten Hag told reporters on Friday.
"Of course I am pushing the team and demanding from the team, and from the start of the season, but they are human beings, not robots, so, why they are not doing it, I try to find out and I try to give the solutions and try to motivate the players to do the job.
"When you are in a period like we are in always as a manager you are asking yourself these questions. My job is to get them to do the job."
Question marks have been raised about the attitude of United's squad, with clips from the Bayern game apparently showing players not chasing back as hard as they might.
Ten Hag does not believe a lack of willingness was to blame, though, saying: "It's always a concern when we didn't run but I think against Bayern it was not the case.
"In certain situations: yes. So it's also to recognise which situation. Is it about they didn't recognise it and didn't make the right decisions or is it about willingness?
"Against Spurs, we didn't run too much. But I think against Bayern we did our best from physical outputs but we didn't always run in the right moment.
"If we bounced back like we did in Munich, you can't say the spirit isn't right. I think we have other problems than that."
AFP