Real Madrid have made initial contact with Juventus over Paul Pogba, sources have told ESPN FC, further complicating the player's anticipated move to Manchester United.

While all those close to negotiations have told ESPN FC that the Old Trafford club remain favourites to sign the 23-year-old French star, they are getting increasingly frustrated with the impasse, ahead of what is described as a make-or-break week for the deal.

Some among the United hierarchy even suspect Pogba may be "stalling them" to see if Real Madrid come in with an official bid.

Juventus are still refusing to budge on their asking price for the player, meaning United will have to get tougher in negotiations, or pay an astonishingly high world-record fee.

Sources say both the club and Jose Mourinho believe they have done all they can, however, and have even considered setting a deadline for the deal to be done or else walking away.

There has long been a suspicion Pogba is still holding out for his first choice and Real finally acted on that in the last 48 hours by making contact with Juventus.

Manager Zinedine Zidane admires the player more than president Florentino Perez does, though, and all those close to the deal still feel it is unlikely that the Spanish club would be willing to pay anything as high as United.

Real have also lined up Newcastle United's Moussa Sissoko for €35 million in the event that they don't sign Pogba.

For their part, United have also been monitoring Blaise Matuidi of Paris Saint-Germain, but the fact are financially stronger than Real at the moment means the likeliest outcome remains Pogba going to Old Trafford.