The Magpies entertain Blackburn at St James' Park next weekend knowing nothing short of a victory will ease a growing sense of impending disaster after a run of 10 Barclays Premier League games without a win.

Marooned on 28 points and without a league victory since December 15, the side Kevin Keegan inherited from Sam Allardyce is being inexorably reeled in by the strugglers who once seemed far distant.

Saturday's 5-1 humiliation at the hands of title hopefuls Manchester United on their own park simply increased the agony as the new manager's wait for a first win extended to six matches.

Harper, whose 100th appearance for the club as a half-time substitute for the injured Shay Given was ruined by a merciless United, admitted the tide has to turn next weekend if Newcastle's plight is not to deepen further.

He said: "It is massive. We have had a tough run of fixtures, but we haven't performed either.

"We have had good spells in patches, but in this league, you have to do it for 90 minutes and until we can do that, we are going to struggle.

"We have got a big week in front of us and in that time, we really need to stick together and build towards Saturday and try to get a positive result.

"We have got some big games coming up. We have got to put this one behind us. It is gone.

"It is a demoralising defeat, but come Monday morning, we are back on the training field and we build up for what is a massive game next week.

"You do need a bit of luck when you are on a run like this, but you need to help yourselves as well and we are not doing that at the minute."

Should the Magpies be dragged into the thick of the fight against relegation - and that will happen sooner rather than later if they do not start the points total ticking over once again - it will not be their 5-1 and 6-0 defeats by United or the 3-0 reverse at Arsenal which will have cost them.

Rather it will be the four points they have gifted Derby this season or their failure to beat Bolton and Middlesbrough at home or to hold on to leads at Boro, Manchester City or Aston Villa.

Even their wins have been far from convincing with the notable exception of their opening day trip to Bolton, where Allardyce's future - little did he realise how short-lived that would be - briefly got the better of his past.

There is little doubt Keegan walked into a mess, but alarmingly, he has as yet been able to do little tangible about it, and United exploited that to the full.

For 25 minutes, Newcastle just about held their own - indeed, skipper Michael Owen flicked a shot wide and had strong appeals for a penalty waved away.

But from the moment Wayne Rooney sauntered on to an inch-perfect Cristiano Ronaldo cross to volley home at the far post, the die was cast.

Ronaldo doubled his side's advantage on the stroke of half-time, racing away from the home defence to convert Michael Carrick's slide-rule pass, and the points were all but won.

The Portugal international repeated the dose within 11 minutes of the restart as the Magpies' soft under-belly was once again cruelly exposed, and although Abdoulaye Faye pulled one back 12 minutes from time, Rooney's clinical second and a fifth from substitute Louis Saha capped a miserable evening on Tyneside.

Harper said: "We are just shooting ourselves in the foot and until we can eradicate that, we are going to have problems.

"It is becoming like a tape recorder playing the same tune over and over again. It is demoralising."

It is Keegan who will have to find the answers, and he remains convinced he will.

He said: "We need to win a football match for the players. They are an honest group of players here who care and I wouldn't say that if I didn't believe it.

"But just being honest and caring is not quite enough in the Premier League."

By contrast, United headed back across the Pennines having taken full advantage of Arsenal's slip-up at Birmingham to reduce their lead at the top of the table to just three points.

Manager Sir Alex Ferguson said: "Just coming and winning with that scoreline tells you a lot about the energy of the team. I thought we looked really fresh.

"I was really pleased with the performance, character and determination of the team to do well."