#4 Victor Lindelof's €35 million tag questionable
Though United ran out comfortable winners in the end, it was not all plain sailing for them. The manner in which the hosts went behind will come under scrutiny, as summer-signing Victor Lindelof was once again guilty of an individual error which led to a goal.
The Swede, who cost United around 35 million, to bring him to Old Trafford from Benfica, was already under fire for a rookie mistake which contributed to United conceding a goal in a 2-1 defeat to Huddersfield in October.
Making his first start in the Premier League, Lindelof 's luck deserted him when he lost his bearings as a low cross was whipped in across the box. Dwight Gayle - who was marked by Lindelof - could barely have had an easier chance to score, as he had all the time available to place his shot with no opposition player close by.
His shot went in off the inside of the post to spark jubilant celebrations in the Newcastle camp.
Lindelof was also caught wandering out of his defensive line and distorting his team's shape when Newcastle came forward.
He did recover thereafter to put in an improved performance, but his discipline and awareness are the major factors which Mourinho must address in order to tangibly justify the lump sum paid for Lindelof's transfer.