A disappointed David de Gea said Manchester United's performances this season have been "unacceptable" after the iconic club lost 1-0 to Newcastle United on Sunday.

Man Utd, who are 12th on the Premier League points table, extended their worst start in 30 years as they are yet to enter the double digits in points with eight matches already done and dusted in the tournament.

"The game isn't acceptable. The whole season isn't acceptable for us. We didn't create any proper chances. We have a lot to improve. I don't know what to say. We need to step up," the Spaniard told Sky Sports.

"We have injuries but it's not an excuse. We are Manchester United. We need to train hard to keep fighting and to get back to winning games," the 28-year-old added.

On Sunday, 19-year-old Midfielder Matty Longstaff scored for Newcastle at the St James' Park Stadium and that handed Man Utd yet another away loss in the Premier League.

The last time Man Utd won an away league game was back in Feburary where The Red Devils defeated Crystal Palace 3-1. The current run is their worst since Sept. 1989 and for De Gea, who joined the iconic club from Atletico Madrid in 2011, it has been the most "difficult" period he has experienced so far at Old Trafford.

David de Gea
David de Gea could make his first appearance of the season for Manchester United in Saturday's clash with Liverpool. Getty Images

"It's probably the most difficult time since I've been here. I don't know what is happening. We cannot score even one goal in two games. Sorry to the fans. We will keep fighting, for sure. We will come back, but at the moment we're in a difficult situation," De Gea, who was bought by Sir Alex Ferguson, added.

Meanwhile, when the goalkeeper was asked in which areas his team needed to improve, De Gea answered, "Everything. A lot of things to improve. Keep trying, keep trying, keep fighting every day. It's a hard moment for us - but we are United and we need to keep fighting."

A massive test awaits Man Utd as they next host Premier League leaders Liverpool FC on Oct. 20, after a brief international break. While Man Utd have won just two games, lost three and drew three, Liverpool are yet to draw or lose a league game this season.