Before Sunday's goalless draw between Tottenham and Manchester United, Sir Alex Ferguson was happy to sing the praises of his right-back Rafael.

"He's not making any rash decisions," the United manager said in the build-up to one of the season's most widely-anticipated games. "He was quite an impulsive young boy last season but he is the kind of thing we invest in and we are getting that return now."

Rafael's dismissal during the game at White Hart Lane following a second yellow card for tripping Benoit Assou-Ekotto may lead to a reassessment of those comments. But former Arsenal right-back and Match of the Day 2 pundit Lee Dixon believes the 20-year-old Brazilian is slowly maturing into a natural successor for Gary Neville.

"I thought we saw all sides of him on Sunday," Dixon said of Rafael. "As a right-back, his main job was to contain Tottenham's in-form winger Gareth Bale - and I think he did a good job, although he did show his naivety at times."

The first of Rafael's cautions came following a first-half tackle on Wilson Palacios and was probably deserved. The second after 74 minutes was "unlucky", according to Dixon. The United defender caught the heels of Assou-Ekotto as the Spurs player was on the attack.

The cruel irony was that Rafael was performing well against Bale up until that point, demonstrating that he could combine defensive duties with attacking forays of his own. That was in contrast to his performance during the 2-0 victory for Manchester United against Spurs earlier this season, when he was also tasked with marshalling the Welshman.

Last October, Rafael kept Bale in check by remaining disciplined, curbing his attacking instincts once United had taken an early lead. On Sunday, with the game remaining goalless, Rafael's ventures down the right flank were far more frequent. Had he shown more composure in the final third, he could have set up chances for his team-mates or even scored himself from two separate opportunities that came his way.

At Old Trafford last autumn, Rafael made only four passes in Tottenham's half. On Sunday, that number rose to 14.

He also showed his attacking intent, with seven dribbles at a success rate of 71%. Bale dribbled the ball four times, with only half of them ending up with a Tottenham player in possession.

In defence, Rafael was never too far from Bale, winning seven of his 11 tackles overall and making four interceptions.

So even though he did not complete either match this term against Tottenham, Rafael certainly contributed to Manchester United's two clean sheets against Harry Redknapp's side - and Tottenham have only been denied a goal on only three other occasions this season.

Dixon believes Rafael's performances have been commendable, particularly against Bale, but thinks harder tests will come when his opponent is not quite so "in his face".

"It can help playing someone like Bale when you are tight on him because you start higher up the pitch anyway," added Dixon. "I still think Rafael has some work to do on his defensive game but Sunday also suited him because he almost went man for man on Bale at times.

"The test for young full-backs is when they haven't got anybody up against them. When do you cover your centre-backs? How much cover do you put on? And where do you need to be in relation to them?

"The position has slightly changed over the years. When I was playing, I could go forward when the ball was on my side of the pitch. When the ball was on the other flank, I would provide cover for the other defenders.

"Today, lots of teams are playing with holding midfield players who sit in front of the back four so you sometimes get both full-backs going forward at the same time."

Rafael had Michael Carrick and Darren Fletcher to thank for offering him that insurance in midfield on Sunday. Centre-back Nemanja Vidic also drew many plaudits for his performance, which Dixon described as "awesome", but Rio Ferdinand's covering role was just as crucial.

As a result, Bale had a mixed day although his pass completion rate and crossing improved compared to the last time these two sides met.

One of his brightest moments came just before half-time, when Spurs defender Michael Dawson fizzed a pass to him. Once Bale had ghosted by Rafael, he crossed for Rafael van der Vaart, who narrowly headed wide.

There was a similar incident earlier in the game but Peter Crouch failed to gamble on getting his head on Bale's cross.

Bale may have to acknowledge that Rafael has come out on top in their two battles this term. But Dixon believes that the Brazilian has a long way to go if he wants to match those who have performed at right-back for United in the past.

"He has a lot of potential and only time will tell if he can play the right-back from a positional point of view," Dixon stated.

"Good full-backs don't get noticed that much if they are in the right position when their team do not have the ball. You might notice them going forward but, as far as defensive duties are concerned, you notice them more when they are not in position than when they are."

If going unnoticed is a good sign, then Rafael certainly has some work to do, given his emotive reaction to being sent off in Sunday's game.

But how would you rate his performance against Bale and what of his future prospects? Have Manchester United finally found the player to replace Gary Neville?

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