United have offered £12m plus winger Nani for the Argentinian,
while Chelsea sporting director Frank Arnesen has been to see him
in action.
But Inter also watched him on Sunday and are now preparing an
offer.
Tug of war: Benfica's Angel Di Maria (right) is
wanted by several clubs
Benfica president Luis Filipe Vieira is determined to keep him,
but says they will not stand in his way if a rival club meets his
release clause in his contract.
Vieira said: 'The player will be allowed to leave in the
transfer window if another club pays the clause in his
contract.
'We need to know what the offer will be and then make a decision
on which is the best value for the club.'
