IF Steve McClaren wanted to show his former boss Sir Alex Ferguson how much he had learned during his time as his lieutenant, well he succeeded.

McClaren is said to be Ferguson's first choice to take over at Old Trafford when the Scot retires at the end of the season.

And, although Saturday's match ended in defeat for Boro, the Red Devils will have been notably impressed by what the Riverside chief has already achieved since taking over in the summer.

The bottle of red wine shared between the two at the end of the clash may have tasted that little sweeter for Ferguson, but McClaren was encouraged by his players' performances against the champions.

Ryan Giggs' introduction as a substitute on 65 minutes proved the difference between the two sides, otherwise Boro matched their more glamorous opponents.

And McClaren believes that United, who have now won their last two matches, can now force their way back to challenge Liverpool for top-spot.

"It would not surprise me if they won the League," said the former United No2 knowing there are just six points between the rivals. "They have got players who can win a game in a second, not just Ryan Giggs who did it for them against us.

"They've won it before even when they were 12 points behind, now it's six.

"You cannot underestimate them, all clubs will fear them because they know eventually they will hit a run.

"Even if you are not playing them, then subconsciously you know if you slip up they will be there.

"It puts pressure on everybody at the top as they know they all need to keep winning.

"They will have been hurt by the criticism levied at them but I know what the manger is like and the players.

"They will not give up, they will fight right until the end - other teams will have to be wary of them."

McClaren will be the first to admit that there is still a long way to go before Boro can seriously push for a top six finish - their 16th placing is testament to that.

But under the York-born manager the Teessiders are methodical, determined and resolute - the only thing missing at the moment is the penetration to score.

Boro have scored just one goal in their last five matches and what will worry McClaren most is that his forwards do not look like finding the net.

Croatian superstar Alen Boksic may have won a lot in the game, but the fans are beginning to turn on the club's top marksman after a lazy display.

Szilard Nemeth was "given a breather" against United after only being able to find the net once in the Premiership since signing from Inter Bratislava in the summer.

Hamilton Ricard, playing his first game since the defeat to Everton on August 25, came in as his replacement.

And despite the Colombian working hard he never troubled United stand-in keeper Roy Carroll.

Boro included former United men Paul Ince and Jonathan Greening in their line-ups and both were obviously fired up to turn on the style against their old employers.

Ince's battling in the midfield epitomised a Boro side who, in the first half in particular, were obviously determined to ensure the visitors were not given space and time on the ball.

And the impressive work-rate of the hosts was something which McClaren admits he picked up from during his time working under Ferguson.

"The platform for any team, any club, is the work ethic," said McClaren, who has adopted the 4-4-2 formation which has proved so successful for Ferguson during his 15-year reign.

"That was the first thing I wanted to instill and that would make us disciplined and determined, we saw evidence of that against United.

"We defended very well. If you keep clean sheets you have always got a chance of getting a result.

"I remember during my time at Man United we won championships on one-nils.

"And I was pleased with the way we played, as I thought we matched them apart from the one 20 minutes spell."

Ferguson, regarded by many as the finest manager in the world, did not field a natural winger on either side of the pitch.

Unbelievably national hero, David Beckham, was not even included among the substitutes, sparking rumours of a rift between player and manager.

Juan Sebastian Veron was played on the right, while Paul Scholes was on the left and neither troubled either Robbie Stockdale or Franck Queudrue.

Veron, who will be taking on England in next summer's World Cup, was brilliant inside but never threatened down the wing and Ferguson switched him to the middle when Giggs came on.

Prior to United getting the elusive goal, the danger signs were there as Mikael Silvestre went close and then Roy Keane fired wide after racing through on Mark Crossley.

But they did not have to wait too much longer when a Giggs dribble provided a goal out of nothing.

The Welshman darted down the left past Stockdale and his shot was not held by Crossley and Ruud van Nistelrooy poked into the net from inside 6 yards.

That was the first goal Crossley had conceded since taking over from Mark Schwarzer in between the posts at Aston Villa - 366 minutes of football.

Both sides had chances to alter the scoreline but a mixture of good goalkeeping and poor finishing meant the Dutchman's strike settled the match.

Boro striker Noel Whelan, on as a second half substitute for Ricard, had a tame shot saved by Carroll.

And then Whelan, playing his first of the season, turned provider when his backheel allowed Ince in, but again Carroll saved.

After spending two-and-a-half years as United's assistant manager McClaren would have loved to have taken at least a point from the clash.

Instead defeat leaves Boro in a disappointing Premiership position and they will be hoping to overcome Fulham at home on Saturday.