The 27-year-old Mata was subbed off at half-time by manager Louis van Gaal as the Red Devils returned to winning ways in the Premier League with an impressive win against the Toffees.
Martial, meanwhile, featured for the whole 90 minutes as United kept to within two points of Premier League leaders Manchester City.
And both Mata and Herrera looked to be enjoying themselves after reporting to Carrington for a light training session on Sunday morning.
Mata posted the picture above on his personal Instagram account and wrote: “Happy Sunday! @martial_9 @manchesterunited”
Mata has started all nine of United’s Premier League games so far this season under Van Gaal, scoring three goals and making three assists.
The 19-year-old Martial, who joined from Monaco on transfer deadline day last month, has started four games and scored three goals in the top flight, notching up one assist.
United are now turning their attentions to their Champions League clash against CSKA Moscow on Wednesday night.
The Red Devils then take on bitter local rivals Manchester City at Old Trafford in the Premier League next Sunday knowing that a win could move them top of the table.
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