Jose Mourinho's men started the season well defensively, but were torn apart by Chelsea during the 4-0 defeat, and the United boss may now look for more defensive reinforcements, as he's claimed to have doubts about his current defenders, believing they are too soft.
Manchester United manager Jose Mourinho
Eric Bailly has shown flashes of being a top defender, but Chris Smalling endured a nightmare performance against Chelsea, Daley Blind has looked shaky at centre back whilst Marcos Rojo appears to be little more than a stand-in.
The Dutchman, 25, has played every minute of Southampton's Premier League campaign so far, and his performances – particularly against Inter Milan in the Europa League on Thursday – have seen the ex-Celtic man earn huge praise.
Southampton's Virgil van Dijk celebrates scoring
Standing at 6ft 4in tall, Van Dijk is dominant in the air, strong in the tackle, athletically gifted with great speed, and even superb on the ball when bringing the ball out from the back, making him the total package at centre back.
It was only a matter of time before clubs started to circle Van Dijk, and Southampton face a real battle keeping him out of United's clutches – a battle they lost with both Luke Shaw and Morgan Schneiderlin in recent years.
Ajax striker Kasper Dolberg
The Mirror also report that United are keen on Ajax striker Kasper Dolberg, who has hit eight goals in all competitions so far this season.
Dolberg, 19, was signed from Silkeborg in 2015, and his superb displays this season are triggering interest as well as comparisons to current United striker Zlatan Ibrahimovic, another Scandinavian striker who made his name at the Amsterdam Arena.
Would you like to see United sign Van Dijk and Dolberg?