Real Madrid have been shocked to the core by an excellent display from Segunda B neighbours
Alcorcon in the Copa del Rey on one of the most embarrassing nights in Madrid's distinguished footballing history.
It was a display of poise, attacking quality, hunger and a will to win from the heroic home side who secured the most memorable night in their 38 year history as a shambolic, disorganised Madrid looked like footballing minnows.
The first half well and truly belonged to the hosts, who dominated Real Madrid from start to finish and the three goal interval lead could have been more as the visitors looked more like the Segunda B side.
Sergio Mora, Ruben Sanz, and Borja all put Jerzy Dudek to the test before Alcorcon eventually took a deserved lead after just 15 minutes as Borja Gomez skipped past the challenge of Mali international Mahamadou Diarra before clipping the ball past the Polish stopper to send the home support into raptures.
Madrid tried to respond but Rafael Van der Vaart's effort lacked conviction and minutes later the Galacticos were two behind. Dutch midfielder Royston Drenthe got caught out of position and Alvaro Arbeloa stuck out his foot to intercept a low cross from the right but managed only to send the ball into the top corner of the net past a hapless Dudek.
Alcorcon were playing the game of their lives and not to be outdone, goalkeeper Juanma joined in with a terrific double save from Van der Vaart and Raul and followed that up with another save, at full stretch to his right to thwart the Dutch attacker once more.
The home side were giving the visitors a lesson in desire and commitment, while exposing Drenthe at left-back once more as Borja continued to probe down that wing and the third inevitably came as Diego Cascon took advantage of Drenthe's absence, firing in a low cross which Ernesto met at the far post to tap home to give the home side an incredible 3-0 half-time lead.
Real introduced Fernando Gago for Guti at the break but the second half continued in similar vein to the first with Alcorcon starting like a team with real ambition. From a free-kick down the right, conceded by Drenthe who was living a nightmare at left-back, Dudek's punch failed to clear the danger and as the ball was played back in Gomez was on hand to coolly slot past the 'keeper into the far corner of the net, from just eight yards, after excellent control with his chest.
It could have been five moments later but Cascon failed to get a touch on a low ball across the box.
As the home side began to tire in the final half hour coach Juan Antonio Anquela made changes with Fernando Bejar and the excellent Ernesto making way for Carmelo and Jeremy.
Madrid enjoyed more possession as the game drew to a close but were restricted to shots from distance as Marcelo and Ruud van Nistelrooy both entered the fray as coach Manuel Pellegrini played all his cards.
What Los Merengues did manage to create in terms of a goal threat was a result of individual craft and not team football and even then Juanma in the Alcorcon goal was rarely troubled as Karim Benzema and sub van Nistelrooy tested him on just a couple of occasions.
Juanma was booked late on for time wasting but Diarra, Guti and Raul Albiol all picked up yellow cards in petulant displays of frustration on a shocking night for Los Blancos.
There is a home leg still to come but on this display it is Alcorcon who deserve to be in the fifth round as Manuel Pellegrini's misfiring Madrid superstars must now face an inquisition of mammoth proportions.