​Jose Mourinho told reporters that there are "many different reasons" for Manchester United's recent run of poor form, but refused to explain any of them in a tense press conference on Friday.

Meeting with the media ahead of Saturday's Premier League match against Newcastle at Old Trafford, Mourinho spoke for less than four minutes. He was asked six questions and answered just five of them, some with only one sentence.

​United are currently on a four-match winless run in all competitions and have only gone five games without victory once since 1999.

Manchester United v Valencia - UEFA Champions League Group H

Asked whether he accepted that such a sequence would be unacceptable for a club of United's stature, Mourinho replied: "Yes, I accept [it is not good enough]."

Mourinho suggested that United's current position of 10th in the Premier League is not reflective of their performances, but he acknowledged that three points against Newcastle is of paramount importance.

"At the beginning of October, you look at tables around Europe and in many of the leagues, the tables don't reflect what is going to happen in a few months or even at the end of the season," he said, quoted by ​Sky Sports News.

"But we are in the position where we can do much better than that. To do that we need points, points that we lost especially in the last two Premier League matches, with one point out of six.

"To improve that position we need to win three points but we know our opponents need the points for different reasons."

United's goalless draw against Valencia on Tuesday means that they have still not won a home match since the opening day of the season against Leicester.

This marks the first time in Mourinho's managerial career that he has gone four home games without a victory.