Jose Mourinho has vacillated between pushing through some more deals and closing up shop ahead next Thursday’s transfer window deadline.

The Manchester United boss had expressed his desire to land a fourth signing after securing Nemanja Matic before backtracking just a matter of weeks later.

He can have few complaints about the state of his squad having added upwards of £315 million worth of new players since arriving at the beginning of last season.

Mourinho – who has deservedly earned a reputation for bringing the best out of a team in his second term at a club – seems to be responding to the pressure in typical fashion.

The Red Devils have enjoyed a promising start to the Premier League with a pair of 4-0 wins over West Ham and Swansea in their first two matches.

One would imagine such impressive results might convince Mourinho to settle for the personnel currently at his disposal until January rolls around.

The arrivals of Victor Lindelof, Romelu Lukaku and Nemanja Matic are a huge plus for United, but they don’t quite complete the jigsaw at Old Trafford.

Mourinho has transformed his team into one of the glitziest in Europe yet neglected to strengthen a position that has caused him headaches since the day he took charge.

PROBLEM POSITION

United have looked susceptible at left-back since Patrice Evra departed for Juventus back in July three years ago.

With neither Daley Blind or Luke Shaw being capable of inheriting the role long-term, Mourinho may regret failing to identify and bring in a suitable candidate this summer.

But that could be set to change with a surprise capture in the dying stages of the window.

The Mirror claims United will target Celtic youngster Kieran Tierney during what little time is left to solve their woes on the left of defence.

We don’t blame you if his name doesn't ring any bells – but United seem to know a thing or two about his talent.

According to former Bhoys striker John Hartson, the 20-year-old is now he Red Devils’ top priority.

”I’m hearing he’s Manchester United’s number one target,” he told the BBC Scottish Football Podcast, per the Sun.

“But why on earth would Brendan Rodgers sell Tierney right now?

“If I’m Brendan Rodgers, I’m saying to [Jose] Mourinho, ‘Let him have another season here, keep your £25-30m for now, he’s got Champions League football, he loves playing for Celtic.

“If Kieran Tierney has another season, if he’s outstanding in the Champions League, playing really well against the top teams, in the spotlight, all over the world being looked at by the top clubs.

“All of a sudden, next year or the year after, you’re getting £45-50m for him.”

Under the guidance of Rodgers at Celtic Park, Tierney has established himself as one of the finest emerging players in the continent.

WHO IS KIERAN TIERNEY?

The Scotland Under-23 international has made 85 appearances for his club and will only attract further attention if he continues progressing at his current rate.

United might uncover a hidden gem if they can get Tierney this summer – but he almost certainly won’t come cheap.

Do United really need to make any more signings this summer? If so, who? Let us know in the comments section below.