Manchester United should refrain from buying a new left-back in January

With Manchester United recording 13 points out of a possible 15 in their opening five encounters, they now sit on top of the Premier League table, level on points and goal difference with cross-city rivals Manchester City.

Optimism has never been higher in the United camp, post-Sir Alex Ferguson's retirement, and for the first time in a very long while, they look like genuine title contenders.

Jose Mourinho has settled on a 4-2-3-1 formation, and for almost every position, he has at least two players good enough for the first team, presenting him with some welcome headaches.

Almost every combination he has tried up front has worked so far, with United banging in 23 goals in just 7 matches.

New signing Nemanja Matic has been a mainstay in midfield, and Jones and Bailly have nailed down the centre back positions, as has Valencia at right back.

But, unfortunately, the same cannot be said down the left.

Jose has experimented with Daley Blind, Ashley Young and Matteo Darmian.

Daley Blind has been employed on the left in the past

Young put up a magnificent performance in the UEFA Champions League against FC Basel at right back, on a night when Valencia was rested following a midweek match against Stoke, which means Young also took over the captain's armband.

The former Aston Villa winger-turned-full back was solid defensively, and also came up with an assist for Fellaini after putting in some excellent crosses into the box.

Against Everton at Old Trafford, he earned himself his first start in the league at left back.

Daley Blind had been decent in the previous matches, but being more suited to centre back, he was occasionally caught out in defence and provided little going forward.

Ashley Young captained United in the Champions League against FC Basel

Unfortunately, that was the same case with Young.

His attacking instincts meant that he was often caught napping when Everton, who almost had nothing working for them that day, found their best attacking moves originate down that flank with their right wing back Cuco Martina.

Going forward, his tendency to cut forward onto his left foot made him predictable, although he did put in some good crosses with his left foot.

The absence of a traditional left-back has not been a drawback for them so far, given the strength in almost every other area of the pitch, but against a top-six opponent, it might cost them.

Luke Shaw is the obvious solution to their problems, but injury has plagued most of his career at United up to this point.

After breaking into the Southampton first team at the age of 17, Louis van Gaal spent around £30 million to bring him to Old Trafford, making him the most expensive English defender at that point of time.

After making only 20 appearances in his debut season, he delivered some of his best performances in a red shirt in 2015/16.

In the Champions League qualification tie against Club Brugge, and in the opening few Premier League fixtures, he showed considerable energy and attacking intent down the left.

The way he combined with new signing Memphis Depay lead many fans to believe that their team had those two positions secured for the future, given that Depay was just 22 and Shaw was 20.

Luke Shaw combined beautifully with Memphis Depay during their time together

But against PSV in the Champions League, Shaw suffered a horrifying double fracture in his leg that ruled him out for the rest of the season, and we all know what happened to Depay.

For the young English defender, it was a cruel nightmare, given that he had just established himself as the undisputed first choice left back under van Gaal.

The following season, van Gaal's departure meant that his future was uncertain, but he did get his chances under Mourinho.

Niggling injury issues once again kept him out for most of the season, as Matteo Darmian and Daley Blind rose above him in the pecking order.

To date, he has made only 48 appearances, a very low number for one of United's most exciting signings in recent times.

He's slowly been recovering this season, having made a few appearances for United's reserves, and made his first senior appearance against Burton Albion in the Carabao Cup, but his lack of match sharpness was apparent.

He came on as a half-time substitute, as Mourinho gave some much-needed rest for Juan Mata.

Shaw lacked his trademark energy and pace down the left, putting in an unusually subdued performance. He didn't make any errors, opting to play it safe, and rarely bursting forward.

On the one occasion that he did, he put the ball in the back of the net after receiving a looping long ball over the Burton defence, but only a couple of seconds after the offside flag went up.

He gave the ball away a couple of times, but recovered well to win it back before any damage was done.

Luke Shaw in action against Burton Albion

One thing was very clear though: he most definitely isn't ready for regular first-team action.

Which means the left back position is still up in the air, and United will almost certainly be linked with a few fullbacks come January.

They had already been linked with Tottenham's Danny Rose and Celtic's Kieran Tierney over the summer, and if rumours are to be believed, they will go back in for one of the two in the winter.

But, United should try and hold back, and not indulge in an unnecessary panic buy.

True, the absence of a world-class player down the left might hurt them going forward this season, especially with the fixture congestion in late December, and against the bigger teams.

United are yet to face last season's top six so far this year.

But, Blind has shown himself perfectly capable of defending down the left, even in big matches.

He struggles in going forward and making overlapping runs, but United have shown themselves perfectly capable of constructing chances from elsewhere on the pitch.

A new signing in January will not only be a needless luxury, it will also be cruelly unfair to Shaw.

To be fair to the lad, he has done well whenever he's given a chance, and if he can avoid injuries, he is still capable of living up to the extraordinary potential that managers like van Gaal and Pochettino saw in him.

The right thing to do now would be to stick to either one of Blind, Young or Darmian for the first team.

They might not be great going forward, but all three of them have displayed defensive resilience on the backfoot.

Meanwhile, Shaw should be allowed some time to regain his form and fitness with the reserves, who will also benefit from his experience.

Let's not forget that he was once considered the most exciting young player to have emerged from the Southampton academy - the same one that produced Gareth Bale.

He made 67 appearances for their senior side at the age of 18, which is a truly remarkable achievement.

In spite of his injury-ridden career so far, he has managed to make 7 appearances for the national side, who also have some other decent left backs in Ryan Bertrand and Danny Rose.

Still only 22 years old, he has every chance of succeeding at Old Trafford if he can achieve better consistency and avoid any more injuries.

If Luke Shaw is ever able to live up to his full potential, he will surely be one of United's best players in the future.