IT WAS fitting, in the week of his investiture as football's newest knight, that Sir Bobby Robson should joust in a battle royal with one of his great adversaries.

The shame was that his fighting men literally couldn't defend themselves against Sir Alex Ferguson's superior forces.

Newcastle's defensive deficiencies when they venture beyond their St. James' Park fortress, are a source of growing concern to manager Robson.

The Magpies have collected 18 Premiership points from a possible 21 at home and conceded only five goals in the process.

Contrast that with their form on their travels - four points from 21 and 17 goals conceded - and it's easy to see why Robson is so perturbed.

His patience is wearing thin and he has warned of a rearguard shake-up. Any one of the back-four - Andy Griffin, Andy O'Brien, Nikos Dabizas and Aaron Hughes - is vulnerable after Saturday's inept showing.

As good as Manchester United were going forward, they were assisted by woeful marking and indecision in the Newcastle defence.

Titus Bramble, when recovered from his hamstring injury, and Steve Caldwell will be in the thoughts of Robson, who has been linked with a New Year swoop for Chelsea's William Gallas.

While Newcastle need to strengthen, a Ruud van Nistelrooy hat-trick and inspirational displays from fellow scorers Paul Scholes and Ole Gunnar Solskjaer, made a nonsense of talk of a crisis at Old Trafford.

When you can carry the absence of six key players - David Beckham, Roy Keane, Rio Ferdinand, Nicky Butt, Gary and Phil Neville - and start with Juan Sebastian Veron on the bench yet perform with such panache, a title tilt is plausible.

Robson knows that and bemoans the fact that his own side, who started the day only a point behind their hosts with a game in hand, still fall short of the Red Devils' standards.

"Manchester United will contest the championship right to the end,'' insisted Robson. "They had six or seven out here, but still fielded a very good side. They won't give it up - it's going to be a great championship race.

"I just wish we were a bit closer ourselves. I said to the players: 'If we're going to be a big side, we have to come to places like this and not lose.' At the moment, we're unable to do that.

"We're inconsistent. Our home record is marvellous. Juventus, with Alessandro del Piero and Pavel Neved, never looked like puncturing us.

"But away from home we have this fragile look. We think we have a good defence, then we come away and suddenly we're vulnerable. It's something I have to think about.

"I hope the players will be quite angry about this defeat and that one or two of them will put their thinking caps on and do better - otherwise they won't be in the team.

"The good thing is we've been to Man. United, Arsenal, Liverpool and Chelsea this season. Now they all have to come to our place, and hopefully the boot will be on the other foot.''

Newcastle never appeared capable of ending their away jinx against Man. United; it is over 30 years since they beat them on their own patch.

Skipper Alan Shearer, who twice turned down a move to Old Trafford, at least had the satisfaction of scoring his 100th Premiership goal for Newcastle at a ground where the home fans love to hate him.

Shearer is the first player to achieve the feat with two clubs; he also plundered a Premiership ton with Blackburn.

But when the moment arrived again on Saturday - Shearer smashed home a 30-yarder in the 51st minute with venom and velocity after Gary Speed rolled a free-kick into his path - it was purely incidental.

A minute later, van Nistelrooy responded by reaching a milestone of his own - his 50th goal for Man. United in all competitions and 14th this season - as he completed his hat-trick.

Robson includes van Nistelrooy among his proteges. "He and I went to PSV Eindhoven at the same time - he was bought by Frank Arnesen,'' said Robson, who recounted the tale of how he urged Ferguson's brother and scout, Martin, to tell the Old Trafford boss to break the bank for £19.5m van Nistelrooy - after being priced out of the hunt himself.

"I was with Newcastle at the time and we couldn't buy him because we didn't have the funds,'' added Robson. "I was sat next to Sir Alex's brother watching van Nistelrooy.

"He was a fantastic boy to work with at PSV and I'm not surprised by what he has done here.''

But it was the outstanding Scholes, in the 24th minute, who launched the latest scoring spree between these sides - their last three meetings have produced 19 goals.

Solskjaer skinned Hughes and when he centred, Scholes rammed into the roof of the net from 12 yards for his sixth goal of the season.

Newcastle levelled in bizarre fashion 11 minutes later. Olivier Bernard felled John O'Shea when he blasted the ball into his face. Bernard then curled the loose ball to the far post where it eluded goalkeeper Fabian Barthez and flew in off the upright.

Talk about adding insult to injury.

But within three minutes, Mikael Silvestre whipped in a cross from the left and van Nistelrooy was able to emerge between Dabizas and Hughes to head in from close range.

Newcastle's defence parted invitingly again when van Nistelrooy scored his second at the end of the first period, Silvestre's pull-back finding Diego Forlan whose slash at the ball skewed it to the Dutchman to knock in from six yards or so.

After Shearer's show of defiance, the same combination set up van Nistelrooy for his treble. Silvestre fed Forlan, who was allowed all the time in the world at the near post to cross for van Nistelrooy to nod in, once more from point-blank distance.

Robson accused the officials of "blatant blindness'' for the home side's fifth when Solskjaer bundled over Hughes on the end of Silvestre's long ball before breaking clear to drill past Shay Given.

Craig Bellamy, recalled by Robson after controversially missing Wales' midweek Euro 2004 qualifier in Azerbaijan with his ongoing knee problem, tested Barthez with a drive before glancing in his third goal in two games from Shearer's header, on the end of substitute Nolberto Solano's corner, in the 74th minute.

Robson wasn't looking for excuses, but he also complained about the state of the playing surface. "The pitch was only relaid a couple of days earlier and it hadn't had time to settle,'' he said.

"It needed maybe ten days. It moved a bit and there was a danger of injuries.''

But even on a level playing field, only one team was ever going to win this game.