The Portuguese is under pressure after United's worst start to a league campaign for 29 years.

His side have not won at Old Trafford since the opening day of the season.

"We can do much better. To do that we need points - points we lost in the last two matches," Mourinho said before Saturday's home game against Newcastle.

Tuesday's goalless home draw against Valencia in the Champions League followed defeat at West Ham, a Carabao Cup exit on penalties to Championship side Derby and a draw with Wolves.

Asked at a news conference on Friday if another match without a victory would not be good enough for a club of United's size, Mourinho replied: "Yes, I accept."

The 55-year-old, who was involved in an apparent training-ground dispute with midfielder Paul Pogba last week, said there were "many reasons" for the winless run, but declined to explain what they were.

He did not answer when asked if he could assure fans he was doing everything possible to turn the team's form around.

United are looking to avoid going five games without a victory for only the second time since 1999.

The Derby result - which Mourinho does not classify as a defeat - followed a 1-1 draw with Wolves at Old Trafford, while United lost 3-0 at home to Tottenham earlier in the season.

"Only one defeat at home all season, only one defeat in the past seven matches," he said.

"But no victories at home in the past three matches - three draws. Not the feeling of the defeat, but not the happiness of the victory.

"So, yes, it is important for us to try and win this match on Saturday."