The Mauricio Pochettino era at Manchester United has officially begun, and the former Chelsea and Tottenham manager will undoubtedly already be looking at how he can improve his squad in the upcoming January transfer window.

The Red Devils find themselves in a precarious position in the Premier League table; they sit 18th, having won just one of their opening ten matches. This dire form is what prompted the Old Trafford hierarchy to make a change in the dugout, dismissing Michael Carrick and appointing Pochettino as the former midfielder's successor.

The Argentine's tenure will commence in practice after the international break when his team visit Anfield, but the work will no doubt start immediately.

The new manager will be devising transfer plans alongside his higher-ups, mapping out ways in which they can bolster the club's roster this winter.

A key area that needs addressing, and could be addressed in January, is left-back, which has been a problem position for United so far this season.

There's 'a Chance' Man Utd Sign a Left-Back in January

The perennially-injured Luke Shaw miraculously featured in all 38 of Manchester United's Premier League matches last season. Given his fitness record, this clean bill of health was unlikely to continue into the new campaign with the addition of Champions League matches, and unsurprisingly, it hasn't.

The England international has been unavailable since October 10th, and United have subsequently been forced to resort to using Diogo Dalot on his weaker side, which hasn't gone well. This is because they failed to sign a competitor for Shaw over the summer, despite courting Newcastle United's Lewis Hall for several months.

The Red Devils' recruitment team decided not to pull the trigger on any of their left-back targets, and instead hold fire until a later date. After seeing how costly this decision has been to their team so far this campaign, they may look to rectify this error in January.

"There's still a chance that with Man United we see a left-back," he said.

"They've looked at David Raum in the past. Antonee Robinson might be a player that a few clubs look at in the winter market, especially if it looks like Fulham are struggling, and there may be some opportunism there, so we will get some winter movement. But there are just two bits of caution. The first is that this inflated market from the summer may bleed over into the winter and put a lot of clubs off spending mid-season. And the second broader point is that the winter market is always a seller's market, not a buyer's market. So it is a lot harder to get the business done."

Jacobs' words of caution suggest a move for Hall might be off the table in January. Newcastle are unlikely to sanction the departure of one of their most important players midway through the season, particularly to a rival.

However, a more modest move for either David Raum or Antonee Robinson certainly feels plausible.

Man Utd Should Make Robinson Pochettino's First Signing

Clearly, signing a left-back should be the priority for United in January. While centre-back and striker are other pressing areas of concern, Pochettino at least has options in these positions. At left-back, it's just Shaw, and perhaps Patrick Dorgu, although the Dane has looked more comfortable further forward in his time in Manchester.

Raum has been a dependable attacking left-back in the Bundesliga for several years now, and would certainly be an adept addition for United to make. That said, there have always been some question marks around his defensive acumen, which is likely the reason behind his inability to secure a move to a top European club.

Meanwhile, Robinson has proven himself in the Premier League over a number of years, both as an offensive outlet and as a reliable defender. On top of this, as Jacobs alluded to, the American could present United with an opportunistic move if he pushes for an exit from Craven Cottage.

Fulham are struggling this season, and this could provide Robinson with leverage in the transfer market, with the West Londoners unlikely to hold one of their longest-serving players hostage, particularly given that his contract expires in 18 months.

It's a no-brainer who Pochettino's first signing should be at Manchester United.