Mata is due to arrive in Manchester today to undergo a medical ahead of his switch to United as their record signing.
United officials are keen to get the Mata deal done as soon as possible, but have been thwarted by Chelsea dragging their heels.
The Blues spent the afternoon finalising terms with Basle for Salah and don't want to release Mata for his £37 million to Old Trafford until they've settled personal terms with Egyptian.
Mata is due to arrive at United's Carrington training HQ by helicopter today to meet boss David Moyes, his new team-mates and have a tour of the training facilities, before undergoing a medical.
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