Louis van Gaal's miserable start to life as Manchester United boss continued with a massive cup shock at the hands of League One MK Dons.
Playing in the League Cup second round for the first time in 19 years, United were mauled by an energetic and clinical performance from the side two divisions below them, who were playing in front of the biggest crowd in their 10-year history.
Four-time winners United did not register a shot on target until the 72nd minute against the team who were only founded in 2004.
Will Grigg scored after a Jonny Evans mistake and then chested in an audacious second after the break.
Benik Afobe, on loan from Arsenal, added two of his own to complete an embarrassing rout for the Premier League giants.
Louis van Gaal admitted after the match that his players "did their utmost best and could do no more"
Having finished seventh in the league last season, the Red Devils entered the second round for the first time since 1995 and with no European football this season, Van Gaal's only chance of silverware this season will be in the FA Cup and Premier League.
But after a defeat by Swansea on the opening day of the Premier League season and Saturday's draw at Sunderland, Van Gaal's reign at Old Trafford will come under even further scrutiny after this lifeless display.
It came on the same night United announced the £60m signing of Angel Di Maria from Real Madrid, becoming the biggest English spenders during this transfer window, but the Argentina international will have his work cut out if he is to instantly mask the fragility demonstrated by a loss to a side put together for less than £500,000.
Benik Afobe made an instant impact for the hosts, scoring with his first touch
There were elements of inexperience in United's line-up, particularly out wide where there were debuts for Saidy Janko and Reece James, who operated either side of the defensive back three that Van Gaal has steadfastly stuck by in his three games in charge.
But a team containing Javier Hernandez, Danny Welbeck, David De Gea, Jonny Evans, Anderson and Shinji Kagawa, who went off in the first half after a blow to the head, still possessed enough top-flight knowhow to look far too strong for a League One outfit.
The return of defender Evans for his first game of the season after an injury lay-off should have been a blessing for United, but it was his horrendous error that had them chasing the game.
Under little pressure near his own goal-line, he inexplicably rolled the ball to Reeves who was able to lay it on for Grigg to finish from 10 yards out.