Manchester United were humiliated 4-0 in their Capital One Cup second-round tie against MK Dons on Tuesday night, the earliest they've been knocked out of the competition in 19 years.
Louis van Gaal made ten changes from the side that drew with Sunderland at the weekend but stuck with his favoured 3-5-2 system.
Two goals each from Dons strikers Will Grigg and then substitute Benik Afobe ensured United slumped to their second defeat of the season.
Grigg scored after a Jonny Evans mistake and chested in a second after half-time. Afobe, on loan from Arsenal, added two of his own to complete United's misery.
This shocking defeat came on the same night that United completed the signing of ex-Real Madrid winger Angel Di Maria for a British record fee of £59.7million.
Van Gaal sent out an inexperienced side, which included debutants Saidy Janko and Reece James in the wing-back roles, however neither seemed comfortable all game.
The amount of youth players in the side can be no excuse though, as Danny Welbeck, Javier Hernandez, Shinji Kagawa, Anderson and David De Gea also started.
The return of defender Evans from injury should have been a promising sign for United, but it was his horrendous error that had them chasing the game after only 25 minutes.
Under little pressure near his own goalline, he rolled the ball to Ben Reeves who was able to lay it on for Grigg to finish from 10 yards.
Slow and lacking creative spark, United continued to put in a frustrating and error-strewn performance, with their stars put to shame by 18-year-old starlet Dele Alli in the MK Dons midfield and forward Reeves, who assisted three of his side's goals.
Reeves provided the cross as part of a counter-attack that Grigg cleverly chested past De Gea and then slid in a wonderful pass to allow Afobe to finish.
Afobe then trundled his way past a string of soft United challenges before calmly scoring his second goal and the Dons' fourth.
MK Dons' biggest ever crowd in their 11-year history roared their team to victory and left Van Gaal stunned and confused on the touchline.
United now head to Burney on Saturday, still looking for their maiden competitive victory under the Dutchman.