Chelsea have made a late move for Real Madrid defender Raphael Varane.
Marca says the news will come as a bitter blow for United who have been edging closer to a £50million deal for the Frenchman.
The West Londoners have emerged as late contenders and could scupper the transfer.
If they can fend off the reported interest from the Blues, United look set to hand over a £50m fee for the centre-back who has just one year left on his Bernabeu contract.
Spanish giants Real initially wanted £60m for Varane but have to sell now to get a fee having lost Sergio Ramos to Paris Saint-Germain on a free.