David de Gea has admitted that Manchester United's form is "unacceptable" following the club's 1-0 defeat to Newcastle United in the Premier League on Sunday.
A debut goal from Matty Longstaff saw United, who hardly created any chances all game, extend their winless run away from home to 11 games.
The result leaves United 12th in the table, just two points above the relegation zone after eight fixtures.
Speaking to BBC Sport ahead of the game, De Gea said: "It is not acceptable, not just this game but the whole season.
"It is the most difficult time since I have been here. I don't know what is happening. We cannot even score one goal in two games."
Defeat at St James' Park means that United have won just two of their last 13 games in the league.
United resume their stuttering campaign after the international break with a home game against Liverpool, who have won every single league game so far this season.
