The English transfer window shuts in just four days, and Manchester United are still linked with a host of players. The latest reports suggest that the club is finally closing in on a R1 billion target of Jose Mourinho's.

Click through the gallery above to see some players who are linked with a switch to United.

The Red Devils boss has made signing a centre-back a priority in this window, but the club is yet to bring in one of his targets. The English giants have been linked with England and Leicester City centre-back Harry Maguire, Bayern Munich's Jerome Boateng and FC Barcelona's Yerry Mina.

However, it now seems they have finally made a breakthrough in negotiations for Tottenham Hotspur and Belgium defender Toby Alderweireld.

United were unwilling to meet Spurs' £75 million (R1.3 billion) asking price for the 29-year-old, whose current contract expires at the end of the 2018/19 campaign. However, Spurs have an option to extend his deal for another year, until the end of 2019/20, but the extension would include a buyout clause of just £25 million (R434 million), as reported by The Guardian.

Mirror Football has now reported there has been a breakthrough in negotiations between both clubs, and United could sign the defender before the window closes.

Alderweireld is reportedly prepared to leave for a cut-price fee in the next window and is apparently not keen on signing a new deal, which leaves Tottenham chairman Daniel Levy with the option of selling him for more than double the price in this window or relatively cheap next year.

Read: Mourinho Warns Man Utd Board

It is believed the two clubs could agree on a £60 million (R1 billion) deal in the coming hours, which would see Mourinho finally get the experienced defender he is after.

Do you think Alderweireld would be a good signing for United? Have your say in the comments section below.