While there are several lessons that can be taken from Saturday's match, one rather stands out—United desperately need to invest in a few players.
Luckily for the Dutchman, the transfer window's closure is still a couple of weeks away; here, we take a look at two stars who could be donning the famous red shirt very soon.
The Daley Blind transfer saga has been dragging on for what feels like a generation now, but it seems that United could be getting their man very soon.
After a remarkable World Cup campaign with the Netherlands under Van Gaal's guidance, the Ajax star's stock rose considerably, with United one of many potential suitors for the versatile defender.
However, the Dutch connection means that Old Trafford is the most likely destination for Blind, whose current manager, Frank de Boer, gave United a boost in their hunt for the 24-year-old by saying that he will be allowed to leave for the right fee—per David Anderson of the Daily Mirror:
We all know that if there is a certain amount on the table we cannot refuse. Then we'll wish him all the best. But I have not heard anything about it, so I am assuming that he still stays for a year. I think it's best for him, but on the other hand, the temptation is there if such a big club comes.
United certainly fit the bill as a big club, and it's safe to say that Blind would be equally big an asset for them should he make the switch.
Tyler Blackett came in as the third centre-back in Van Gaal's three-man defence against Swansea City, and though the 20-year-old is a talented player, he's not quite ready for Premier League action.
That's not to quote the famous phrase of "you don't win anything with kids," but Van Gaal needs a player with more experience and proven quality at the highest level—something that Blind certainly has.
Valued at around £15 million, the Dutchman appears somewhat of a bargain from United's perspective. It's just a case of getting the man himself to agree to the move.
However, as Sky Sports' Pete O'Rourke revealed, Blind is open to a Premier League switch:
All that's left to do now is make the move happen, and while transfer window acquisitions are usually luxury signings for United, the Blind chase is more of a necessity.
While the defeat to Swansea City made Manchester United's defensive frailties crystal clear, it has also put their centre midfield under the spotlight.
Though new signing Ander Herrera fitted like a glove into United's system, the performances of Marouane Fellaini and Darren Fletcher left a lot to be desired.
Van Gaal's side so sorely needed a midfielder with a bit of penetration to unlock the stubborn Swansea defence—a player like Juventus' Arturo Vidal.
United have been linked with the Chile international for some time now, but luring the £40 million man to Old Trafford has proved an extremely difficult task.
Some fans may well have given up hope at this point in the transfer window, but they now have reason to be slightly optimistic.
As Anthony Chapman of the Daily Express reported, Vidal himself has revealed that his future in Turin is uncertain. When asked about his future at the club, he cheekily responded, "My future is to train well..."
Vidal is hardly dedicating his life to Manchester United with his statement, but it seems that we could be hearing a lot more of his name in the coming weeks.
However, ESPN's Johnathan Johnson doesn't seem to think that the move will go ahead despite Vidal's words, as he said via Twitter:
The yo-yo saga goes on, but if Van Gaal really wants to challenge for silverware this season, then Vidal is the calibre of player he needs to be signing.
Adding the Chilean and Blind into his setup at Old Trafford won't miraculously make things perfect for United, but it'll certainly be a step in the right direction.