Manchester United edged past a resilient SL Benfica side thanks to an own goal from Mile Svilar, followed by a Daley Blind penalty in their fourth Champions League game of the season.
The Red Devils might have won the game by a greater margin had Anthony Martial converted the first penalty awarded to United.
The home side made a promising start to the European encounter and were gifted a golden opportunity to take the lead when Anthony Martial was brought down by Douglas in the penalty box. The Frenchman stepped up to take the resulting spot kick but it was saved by the 18-year-old Benfica stopper Mile Svilar.
The teenage keeper went from hero to zero half an hour later when Nemanja Matic's effort crashed off the post and onto the back of Svilar which resulted in the ball rolling across the goal line to give the Red Devils the advantage.
Mile Svilar now holds the Champions League records for youngest keeper to save a penalty and to score an own goal. Meanwhile, Manchester United's club record signing Romelu Lukaku had the chance to double the lead but Svilar made another good save to keep Benfica in the game.
The away side's best chance came with 25 minutes left of the match, Eric Bailly's sloppy pass was pounced on by Raul Jiminez but the Mexican striker could only poke his effort onto the post as David de Gea stood rooted to the spot.
All hope of a Benfica comeback was exstingiushed in the 78th minute when Manchester United were awarded their second penalty of the game, following a poor challenge from Jardel on Marcus Rashford. Daley Blind stepped up and smashed a low hard strike down the centre of the goal to seal all three points for the Red Devils,
Jose Mourinho's team just need a point from their remaining two Champions League games to secure qualification to the knockout phase of Europe's elite club competition