Erik ten Hag is facing a potentially decisive four days in his tenure - starting on Thursday night. The Estadio do Dragao in Porto might have been the grand stage on which Jose Mourinho first caught the world's spotlight but, for the current Manchester United manager, it could well be the scene for one of his final acts at the club if he falls to another defeat.
Ominously, United's only two losses in eight matches with Porto have come in Portugal. However, the hosts come into this week's clash on the back of a shock defeat to Bodo/Glimt on the opening game-week, having already lost ground to main rivals Sporting Lisbon in their domestic title race. ALSO READ: Ten Hag is out of his depth - and it's time for him to go ALSO READ: United are set to stick with Ten Hag after sack decision United can, nevertheless, expect a hostile atmosphere at the Dragao and have pressures of their own to combat having only drawn 1-1 with FC Twente last week.
Anything but a win would hinder United's top-eight qualification hopes and further crank up the pressure on Ten Hag. A subsequent trip to Aston Villa on Sunday afternoon is hardly a reprieve, either.
A win in Europe would cool some of the heat on Ten Hag, but an adverse result there and at Villa Park - which will be rejuvenated from their first top-tier European night for 41 years - would reset the velocity of noise.