Man Utd believe 'matter of when, not if' they complete deal for Barcelona star De Jong.
The Netherlands international is returning from vacation this week because United and Barca have made an improved offer to sign him.
The Manchester Evening News quotes United club sources as saying that the deal's completion is "a matter of when, not if." Erik ten Hag, the newly appointed United manager, is eager to capture De Jong as his first player after working with the 26-year-old at Ajax.
United's initial bid was for €60 million, but Barca wants a guaranteed €75 million (£64.55 million) plus add-ons.
Old Trafford sources claim that the club is "negotiating hard" to come to a deal with the La Liga heavyweights.