The Reds are said to have come to terms over a £17 million move with the Portuguese giants, with Garay expected to move to Old Trafford this summer.
The Argentinian international has been linked with a host of clubs including Chelsea and Barcelona in recent weeks, but the Premier League leaders looked to have moved quickly to fend off those advances and secure their man.
With Nemanja Vidic and Rio Ferdinand each missing large chunks of the season through injury, Sir Alex Ferguson has identified a top-class central defender to come in for the long term, and Garay appears to be the solution.
The 26-year-old has been integral to Benfica's ascent to the top of the Portuguese Premier Division, and a move away from the Estadio da Luz has looked on the cards for a while.
Garay initially rose to prominence with Spanish side Racing Santander after moving from Newell's Old Boys as a teenager, and his form at the El Sardinero convinced Real Madrid to sign him in the summer of 2008.
But after failing to command a starting spot at the Bernabeu, he was offloaded to Benfica in July 2011 and has gradually regained the reputation which made him so sought after earlier on in his career.
Garay has picked up 11 international caps for Argentina and was part of Alejandro Sabella's La Albiceleste side which secured an impressive 3-0 win over Venezuela on Friday night.
The 6'4" central defender looks to have the pace, mobility and physicality to handle life in English football, and his assured ball playing from the back will be a welcome addition to the Reds squad.
The £17 million price tag also looks good value for all parties, and if Garay can maintain the performances he has shown for Benfica, United will have once again done a shrewd bit of business for a player at the peak of his powers.
Nothing has been officially confirmed by either club as yet, but the Express quote Portuguese publication Record in saying the deal has been agreed.
Do you think Garay is the long-term solution to United's central defensive problems, and will he adjust to the rigours of the Premier League?
If not Garay, then who would you go for to add steel to United's back line?
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