The Dutchman's reign got off to a disappointing start on Saturday afternoon, as goals from Ki Sung-Yueng and Gylfi Sigurdsson handed Swansea City a shock win at Old Trafford, with Wayne Rooney's equaliser not enough to hand United points on the opening day of the season.
Van Gaal was left with a decimated squad to pick from, with his starting line-up featuring youngster Tyler Blackett at centre back, as well as playmaker Jesse Lingard and winger Ashley Young as the starting wing backs. If anything, the the defeat against the Swans should give United the kick they need to go and make more signings ahead of the transfer deadline.
However, for the Swans, it was a huge boost. Things turned sour under Michael Laudrup last season, and club hero Garry Monk has taken the reins on a full-time basis having ended the season as caretaker manager. Returning loanee Ki and ex-midfielder Sigurdsson have both come back to try and take the club forward, and they proved how valuable they could be with their goals against United.
With World Cup stars Jefferson Montero and Federico Fernandez now set to make an impact in South Wales, the future is looking bright - if they can keep hold of top goalscorer Wilfried Bony, who is attracting interest from the likes of Liverpool and Tottenham.
For now though, the Swans can bask in the glory of their win at Old Trafford - where they played the party-pooper role to perfection with their great passing and swift counter attacking.