THE sort of refereeing decision that provides Manchester United's ever-growing army of critics with sufficient ammuntion to last them a season undermined Middlesbrough's attempts to replicate March's win at Old Trafford.

With 27 minutes having elapsed last night and Boro frustrating United's efforts to break them down, Ruud van Nistelrooy found a yard of space inside the Middlesbrough penalty area.

As he fell under the mildest of challenges from Ugo Ehiogu, van Nistelrooy managed to scoop a shot over the crossbar on the half-volley.

Immediately, he turned to referee Mike Riley pleading for a penalty, and the official - whose Leeds roots have caused him to be on the receiving end of at least one public tirade from Sir Alex Ferguson in recent seasons - pointed to the spot.

Contact between the pair was minimal - Ehiogu's outstretched hand glanced rather than grabbed van Nistelrooy's arm - and tellingly there were no more than muted appeals from the other United players and the home fans.

Yet Riley was unequivocal, and one always sensed that van Nistelrooy - like Liverpool's Michael Owen against Newcastle United 24 hours earlier - would not pass up such a glorious opportunity to open his Premiership goalscoring account for the season.

He rammed home the spot-kick, straight and true into the roof of the net, and Middlesbrough were grateful that they were not a man down as well as a goal down, Ehiogu having been shown the yellow card for his "offence".

Van Nistelrooy, of course, was at the centre of a 'diving' storm after winning a penalty in United's 1-0 win at Ipswich Town in April.

But the knowledge that they were unjustly beaten will have been of little comfort to Boro as they made their weary way back to Teesside last night, having almost written another chapter in their book of Old Trafford successes.

Winners away to United in two of the last four seasons, Boro could easily have taken a precious point into the international break.

Not that Boro dominated after going behind, though.

United still had the lion's share of possession, but there were a handful of heart-stopping moments for the home team before they clinched victory.

Fabien Barthez fumbled a stinging George Boateng drive past a post, while the United goalkeeper was able to smother a late header from Joseph-Desire Job.

Rio Ferdinand also had to block a Job shot in stoppage time, but it was Boro's defensive organisation and resilience rather than their invention in attack that merited a point.

For almost half-an-hour, Steve McClaren's gameplan worked a treat. Boro were strangling the life out of the game as United, with van Nistelrooy a lone striker, foundered against the visitors' five-man defensive unit.

With Roy Keane, the heartbeat of United's team, absent after hip surgery, the seven-time Premiership champions were devoid of drive from midfield.

For all David Beckham's qualities - world-class footballer and perfect father apparently being among them - one cannot expect to see United's stand-in captain, fists pumping, urging his troops forward.

Boro could not claim that they were asking many questions of the United defence, and a one-two between Job and Massimo Maccarone that forced Barthez and Laurent Blanc to snuff out the danger was one of their precious few bright spots early on.

But containment was Boro's primary aim, and they did that very well thank you very much for most of the opening stanza.

The first sign that the tide might be turning against Boro came after 25 minutes. Ryan Giggs embarked on a scorching 50-yard run before unleashing a fierce angled drive that had Mark Schwarzer grabbing nothing but a handful of air but flew just wide.

While that attack was conceived midway inside the United half, the penalty was awarded after a quick interchange of passes in and around the Boro 18-yard box.

Beckham found Giggs in enough space to allow the Wales winger to flick the ball, first time, beyond the Boro backline and into van Nistelrooy's path.

One could argue that Ehiogu ought not to have afforded Riley, who had already given several questionable decisions United's way, the opportunity to award a penalty.

But the decision was still ultra-harsh, and the relief that swept around Old Trafford when van Nistelrooy scored was matched only by the burning sense of injustice emanating from those whose loyalty lay with Middlesbrough.

Still Boro could have been level at half-time, though, with Ferdinand - on his home league debut - backheeling the ball to safety with Barthez stranded and Job waiting to turn home Robbie Stockdale's delicious cross.

Maccarone might have got on the end of that centre, but he seemed to hesitate as it arced towards the danger area.

That seemed to sum up the Italian's evening. Job, making his first Premiership start since August 25, 2001, was always Boro's most lively striker and Maccarone made way for Noel Whelan 18 minutes from time.

Before he departed, Maccarone was presented with the kind of opening that Boro's record signing must have spent the entire evening praying would fall his way

The ever-willing Job worked an opening for Maccarone, but instead of drilling his shot beyond the exposed Barthez and into the net his effort flashed well wide of the near post.

Middlesbrough went closer in the dying stages, but United stayed in front with only a modicum of discomfort.

It was the manner in which they went in front that left a sour taste long after Riley blew the final whistle.

l Sir Alex Ferguson last night pulled David Beckham out of the England squad to face Portugal on Saturday. The Manchester United boss claimed Beckham is suffering from a calf strain.

Result: Middlesbrough 0 - Manchester United 1.

Read more about Middlesbrough here.