Jesse Lingard came off the bench against the club where he performed so well on loan last term and curled a beauty into the top corner of the net. There was still time, after Cristiano Ronaldo was inexplicably denied two penalties, for Mark Noble to have a spot-kick saved at the death after VAR decided Luke Shaw's handball in the box needed reviewing.
Ronaldo had earlier cancelled out the opening goal by Said Benrahma in the first half.
The Reds slipped behind in unfortunate circumstances as Benrahma's shot deflected in off Raphael Varane to wrong-foot David De Gea.