Manchester United secured the headline signing of the January transfer window in eclipsing their previous record fee paid by landing Juan Mata for £37.1 million. But as Saturday’s defeat to Stoke City again demonstrated there is much work to be done at Old Trafford. Indeed, the signing of Mata can be seen in many ways as sticking a cherry on a non-existent cake. Mata, while a player of undeniable quality, failed to address the squad’s major need.

There are of course problems that go beyond the squad. David Moyes, ultimately has a better squad of players than that which romped to the Premier League title last season. Sir Alex Ferguson is certainly a managerial genius for extracting what he did out of his players in recent years, but Moyes cannot be absolved from blame for the side being 15 points off the pace and having lost a third of their matches in the league this campaign.

Whether Moyes is in charge or not to make the decisions, some major signings will be needed to get the club performing on the pitch in a manner befitting their reputation.

Here are four players who should be targeted:

Arturo Vidal (Juventus)

Mata will provide touches of class in the final third, but if there is one player who could have transformed the United team in one fell swoop it may well have been the Chilean midfielder. Vidal can do everything you could ask from a central midfielder. Only one player averages more tackles in Serie A this season, according to stats website Meanwhile, he can also create with the ball at his feet and his ability to get forward has seen him net 11 goals in 22 appearances. Juventus won’t be at all eager to sell, but it would be worth offering a ridiculous sum for a player who is just entering the prime of his career.

Paul Pogba (Juventus)

As has been explicitly laid bare by his hand-picking of David Moyes as his replacements, Ferguson’s judgment is not always impeccable. His failure to keep Pogba at the club may go down as one of his greatest missteps. Of course, it’s not as simple as saying that Manchester United let him go when he moved to Juventus on a free transfer in 2012, but it’s also surely true that more could have been done to keep him. Pogba should have been much more involved in the first team, where the midfield competition was hardly overwhelming, while it would have proved wise to be acquiescing to the demands of his agent, even if they appeared exorbitant for a then teenager. It will certainly cost them far more to bring him back to Old Trafford now, although as Chelsea have decided with their re-signing of Nemanja Matic, it may prove to be some humble pie worth devouring.

Luke Shaw (Southampton)

The pursuit of Leighton Baines last summer made little sense. Patrice Evra was coming off a much-improved season and, while he would soon need replacing, it made no sense to spend big money to replace him with a left-back who is only three-and-a-half years his junior. Far more logical, both then and now, would be to move for Southampton youngster Shaw. From his first appearances in the Premier League last season, the 18-year-old looked destined to be a fixture for England for more than a decade. Displaying natural defensive awareness as well as the ability to be a consistent threat going forward, Shaw is arguably worth the reported £25 million plus it would take to prize him away from Southampton.

Mehdi Benatia (Roma)

With Rio Ferdinand looking increasingly likely to leave when his contract expires in the summer and Nemanja Vidic, as a result of age and injuries, a notch below the immovable force of a few years ago, a central defender should also be on the wanted list in the summer. In that aim, Manchester United would be wise to look strongly at Morocco international Benatia. Having arrived from Udinese last summer, the 26-year-old has been a key part of Roma having the best defensive record in Serie A this season. Adding to Benatia’s appeal is his passing ability and the aerial threat he poses in the opposition box,  

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