Manchester United manager Louis van Gaal said he and his team deserved to be booed by fans after the 1-0 loss to Southampton at Old Trafford.
United failed to score a first-half goal for the 11th home game in a row, before Charlie Austin got the winner in the 87th minute.
United are fifth in the Premier League, five points behind fourth-placed Tottenham and 10 off leaders Leicester.
"They are right to boo. I cannot deny that, I saw the match," said Van Gaal.
"For better or for worse we have to stick together," added the Dutchman after his side's six league defeat of the season.
United have taken 37 points from their first 23 games, their lowest total in the Premier League era and three points fewer than under David Moyes during the 2013/14 season.
Van Gaal added: "We are working very hard, but we have had a lot of injuries. That you cannot change."
Darmian taken to hospital
On Saturday, United were without Ashley Young, who Van Gaal says faces "a long time" out with a serious groin injury, and lost fellow defender Matteo Darmian mid-way through the second-half following a clash with Shane Long.
Van Gaal revealed that the Italian was "spitting blood" after leaving the pitch and had gone to hospital.
If the 26-year-old is now sidelined it will leave United without a fit senior full-back, with Luke Shaw still out after suffering a double fracture of his right leg last September.
United's woe in numbers
|Manchester United managers in the Premier League|
|Sir Alex Ferguson (1986-2013)||810||528||65.2|
|David Moyes (2013-14)||34||17||50|
|Ryan Giggs (2014)||4||2||50|
|Louis van Gaal (2014-Present)||61||30||49.2|