Nathaniel Ake would score five minutes later to seal the victory for Pep Guardiola’s side.
Man United manager Erik ten Hag admitted his side displayed a horror show in the opening minutes of the match.
Referee Paul Tierney missed the initial incident, but after consulting the VAR screen, he awarded United a penalty, which Bruno Fernandes duly converted.
This victory becomes United’s thirteenth straight home win across all competitions this season.
The goal is Marcus Rashford’s 100th Premier League goal contribution for Manchester United.
Manchester United duo of Bruno Fernandes and Casemiro netted the winners in both important fixtures.
Portugal defeated the Nigerian Super Eagles 4-0 on Thursday in a friendly match.
Manchester United came from behind twice to hammer Aston Villa 4-2 at Old Trafford.
Manchester United had not won successive games in the league since February.
Manchester United’s UEFA Champions League qualification chances received a boost on Saturday after Tottenham and Arsenal fell to shock losses.
