United head into the fifth-round tie at Greenhous Meadow in considerable need of an upturn in results, their previous two outings having been 2-1 defeats in the Barclays Premier League at Sunderland and Europa League last 32 at FC Midtjylland.
Bouncing back with a win against League One Shrewsbury, followed by another in leg two of the European tie three days later at Old Trafford sufficient to send them through would provide a significant boost.
And if United could add a third victory in next Sunday's Premier League home clash with Arsenal, it would make for a very good week indeed, with some momentum regained and the Red Devils still in the hunt for two trophies as well as a top-four finish.
It is certainly a realistic target - but after Van Gaal's men were so lacklustre in the sorry reverse at Midtjylland on Thursday, there would also appear to be every chance they could endure further struggles over the coming days.
And if it proves a bad week results-wise, Van Gaal's position will surely be looking nothing short of precarious.
The latest losses have led to another surge in talk of the Dutchman's tenure nearing its end and Jose Mourinho being set to come in as his replacement.
There have been some suggestions Van Gaal may have just the three games ahead to save himself from the sack, while Mourinho has been quoted as saying he has no plans to return to managing Inter Milan next season, and adding: ''I'm not looking for a club, but there are clubs that are looking for me.''
United defender Chris Smalling has joined team-mate Michael Carrick in labelling Thursday's display in Denmark unacceptable and stressing the need for the players to start delivering more for the club's supporters.
Reflecting on the Midtjylland game, Smalling told MUTV: "It was a performance that wasn't acceptable.
"We need to start rewarding these fans who travel so far and give us great support throughout the whole game
I think we all know that it wasn't good enough.
"Conceding before half-time didn't help (Midtjylland made it 1-1 in the 44th minute), we didn't really kick on with that belief in the second half, and I think we lost far too many tackles and a lot of second balls.
"I think in these games when you play teams that are lesser than Manchester United, you need to win your tackles and second balls.
"When you don't do that, then it is an even playing field on the pitch
So I think that we've only got ourselves to blame for the result."
With first-choice goalkeeper David De Gea injured, United have recalled 18-year-old Dean Henderson from his loan spell at Conference North side Stockport as cover for Sergio Romero, and the teenager could be on the bench at Shrewsbury.
Source : PA
Source: PA