#2 MK Dons 4 Manchester United 0 (August 2014)
Will Grigg was on fire, and Louis van Gaal's defence was actually terrified. Rewind to August 2014, and the Dutch manager took charge of his first domestic cup match in English football against Karl Robinson's MK Dons.
What soon followed was nothing short of remarkable as van Gaal's side went down 4-0 losers to the League One team. Manchester United were playing their first Capital One Cup Round 2 fixture in 19 years after the Red Devils finished a pitiful tenth place under David Moyes the season before.
(Video Courtesy: ShivDes357 YouTube Channel)
Still, with not many expecting the southern's to scalp the 13-time Premier League champions, Will Grigg and Benik Afobe both scored twice to guarantee a place in the third round.
After a defeat by Swansea on the opening day of the Premier League season followed by a draw at Sunderland, van Gaal's reign at Old Trafford didn't get off to a great start. It's a result that still haunts United's enormous fanbase.